672 (number)
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600 (six hundred) is the
natural number In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country"). Numbers used for counting are called ''cardinal ...
following 599 and preceding 601.


Mathematical properties

Six hundred is a
composite number A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Equivalently, it is a positive integer that has at least one divisor other than 1 and itself. Every positive integer is composite, prime, ...
, an
abundant number In number theory, an abundant number or excessive number is a number for which the sum of its proper divisors is greater than the number. The integer 12 is the first abundant number. Its proper divisors are 1, 2, 3, 4 and 6 for a total of 16. Th ...
, a
pronic number A pronic number is a number that is the product of two consecutive integers, that is, a number of the form n(n+1).. The study of these numbers dates back to Aristotle. They are also called oblong numbers, heteromecic numbers,. or rectangular number ...
and a Harshad number.


Credit and cars

* In the United States, a credit score of 600 or below is considered poor, limiting available credit at a normal interest rate. *
NASCAR The National Association for Stock Car Auto Racing, LLC (NASCAR) is an American auto racing sanctioning and operating company that is best known for stock car racing. The privately owned company was founded by Bill France Sr. in 1948, and ...
runs 600 advertised miles in the
Coca-Cola 600 The Coca-Cola 600, originally the World 600, is an annual NASCAR Cup Series points race held at the Charlotte Motor Speedway in Concord, North Carolina, on a Sunday during Memorial Day weekend. The first race, held in 1960, was also the first on ...
, its longest race. * The
Fiat 600 The Fiat 600 ( it, Seicento, ) is a rear-engine, water-cooled city car, manufactured and marketed by Fiat from 1955 to 1969 — offered in two-door fastback sedan and four-door Multipla mini MPV body styles. Measuring only long, its all-n ...
is a car, the
SEAT 600 The SEAT 600 is a city car made in Spain by SEAT from May 1957 until August 1973 under licence from Fiat. It helped to start the Spanish miracle (economic boom of 1959–1973) that came at the end of the slow recovery from the Spanish Civil War. ...
its Spanish version.


Integers from 601 to 699


600s

* 601 = prime number,
centered pentagonal number A centered pentagonal number is a centered figurate number that represents a pentagon with a dot in the center and all other dots surrounding the center in successive pentagonal layers. The centered pentagonal number for ''n'' is given by th ...
* 602 = 2 × 7 × 43,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, number of cubes of edge length 1 required to make a hollow cube of edge length 11, area code for
Phoenix, AZ Phoenix ( ; nv, Hoozdo; es, Fénix or , yuf-x-wal, Banyà:nyuwá) is the capital and most populous city of the U.S. state of Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United Stat ...
along with
480 __NOTOC__ Year 480 (Roman numerals, CDLXXX) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Basilius without colleague (or, less frequ ...
and 623 * 603 = 32 × 67, Harshad number, Riordan number, area code for
New Hampshire New Hampshire is a state in the New England region of the northeastern United States. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Gulf of Maine to the east, and the Canadian province of Quebec to the nor ...
* 604 = 22 × 151,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, totient sum for first 44 integers, area code for southwestern British Columbia (Lower Mainland, Fraser Valley, Sunshine Coast and Sea to Sky) * 605 = 5 × 112, Harshad number, sum of the nontriangular numbers between the two successive
triangular numbers A triangular number or triangle number counts objects arranged in an equilateral triangle. Triangular numbers are a type of figurate number, other examples being square numbers and cube numbers. The th triangular number is the number of dots i ...
55 and 66, number of non-isomorphic set-systems of weight 9. * 606 = 2 × 3 × 101,
sphenic number In number theory, a sphenic number (from grc, σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. Because there are infinitely many prime numbers, there are also infinitely many sphenic numbers. Definit ...
, sum of six consecutive primes (89 + 97 + 101 + 103 + 107 + 109), admirable number * 607 – prime number, sum of three consecutive primes (197 + 199 + 211),
Mertens function In number theory, the Mertens function is defined for all positive integers ''n'' as : M(n) = \sum_^n \mu(k), where \mu(k) is the Möbius function. The function is named in honour of Franz Mertens. This definition can be extended to positive re ...
(607) = 0, balanced prime, strictly non-palindromic number,
Mersenne prime In mathematics, a Mersenne prime is a prime number that is one less than a power of two. That is, it is a prime number of the form for some integer . They are named after Marin Mersenne, a French Minim friar, who studied them in the early 17th ...
exponent * 608 = 25 × 19,
Mertens function In number theory, the Mertens function is defined for all positive integers ''n'' as : M(n) = \sum_^n \mu(k), where \mu(k) is the Möbius function. The function is named in honour of Franz Mertens. This definition can be extended to positive re ...
(608) = 0,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
,
happy number In number theory, a happy number is a number which eventually reaches 1 when replaced by the sum of the square of each digit. For instance, 13 is a happy number because 1^2+3^2=10, and 1^2+0^2=1. On the other hand, 4 is not a happy number because ...

number of regions formed by drawing the line segments connecting any two of the perimeter points of a 3 times 4 grid of squares.
* 609 = 3 × 7 × 29,
sphenic number In number theory, a sphenic number (from grc, σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. Because there are infinitely many prime numbers, there are also infinitely many sphenic numbers. Definit ...
, strobogrammatic number


610s

* 610 = 2 × 5 × 61, sphenic number,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
,
Fibonacci number In mathematics, the Fibonacci numbers, commonly denoted , form a sequence, the Fibonacci sequence, in which each number is the sum of the two preceding ones. The sequence commonly starts from 0 and 1, although some authors start the sequence from ...
,
Markov number A Markov number or Markoff number is a positive integer ''x'', ''y'' or ''z'' that is part of a solution to the Markov Diophantine equation :x^2 + y^2 + z^2 = 3xyz,\, studied by . The first few Markov numbers are : 1, 2, 5, 13, 29, 34, 89 ...
. Also a kind of telephone wall socket used in Australia. * 611 = 13 × 47, sum of the three standard board sizes in Go (92 + 132 + 192), the 611th
tribonacci number In mathematics, the Fibonacci numbers form a sequence defined recursively by: :F_n = \begin 0 & n = 0 \\ 1 & n = 1 \\ F_ + F_ & n > 1 \end That is, after two starting values, each number is the sum of the two preceding numbers. The Fibonacci seque ...
is prime * 612 = 22 × 32 × 17, Harshad number, Zuckerman number , area code for
Minneapolis, MN Minneapolis () is the largest city in Minnesota, United States, and the county seat of Hennepin County. The city is abundant in water, with list of lakes in Minneapolis, thirteen lakes, wetlands, the Mississippi River, creeks and waterfalls. ...
* 613 = prime number, first number of
prime triple In number theory, a prime triplet is a set of three prime numbers in which the smallest and largest of the three differ by 6. In particular, the sets must have the form or . With the exceptions of and , this is the closest possible grouping of ...
(''p'', ''p'' + 4, ''p'' + 6), middle number of
sexy prime In number theory, sexy primes are prime numbers that differ from each other by 6. For example, the numbers 5 and 11 are both sexy primes, because both are prime and . The term "sexy prime" is a pun stemming from the Latin word for six: . If o ...
triple (''p'' − 6, ''p'', ''p'' + 6). Geometrical numbers:
Centered square number In elementary number theory, a centered square number is a centered figurate number that gives the number of dots in a square with a dot in the center and all other dots surrounding the center dot in successive square layers. That is, each cen ...
with 18 per side, circular number of 21 with a square grid and 27 using a triangular grid. Also 17-gonal. Hypotenuse of a right triangle with integral sides, these being 35 and 612. Partitioning: 613 partitions of 47 into non-factor primes, 613 non-squashing partitions into distinct parts of the number 54. Squares: Sum of squares of two consecutive integers, 17 and 18. Additional properties: a
lucky number In number theory, a lucky number is a natural number in a set which is generated by a certain "sieve". This sieve is similar to the Sieve of Eratosthenes that generates the primes, but it eliminates numbers based on their position in the remain ...
, index of prime Lucas number. ** In
Judaism Judaism ( he, ''Yahăḏūṯ'') is an Abrahamic, monotheistic, and ethnic religion comprising the collective religious, cultural, and legal tradition and civilization of the Jewish people. It has its roots as an organized religion in t ...
the number 613 is very significant, as its metaphysics, the
Kabbalah Kabbalah ( he, קַבָּלָה ''Qabbālā'', literally "reception, tradition") is an esoteric method, discipline and school of thought in Jewish mysticism. A traditional Kabbalist is called a Mekubbal ( ''Məqūbbāl'' "receiver"). The defin ...
, views every complete entity as divisible into 613 parts: 613 parts of every
Sefirah Sefirot (; he, סְפִירוֹת, translit=Səfīrōt, Tiberian: '), meaning '' emanations'', are the 10 attributes/emanations in Kabbalah, through which Ein Sof (The Infinite) reveals itself and continuously creates both the physical realm an ...
; 613 mitzvot, or divine Commandments in the
Torah The Torah (; hbo, ''Tōrā'', "Instruction", "Teaching" or "Law") is the compilation of the first five books of the Hebrew Bible, namely the books of Genesis, Exodus, Leviticus, Numbers and Deuteronomy. In that sense, Torah means the ...
; 613 parts of the human body. ** The number 613 hangs from the rafters at Madison Square Garden in honor of New York Knicks coach
Red Holzman William "Red" Holzman (August 10, 1920 – November 13, 1998) was an American professional basketball player and coach. He is best known as the head coach of the New York Knicks of the National Basketball Association (NBA) from 1967 to ...
's 613 victories. * 614 = 2 × 307,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, 2-Knödel number. According to Rabbi
Emil Fackenheim Emil Ludwig Fackenheim (22 June 1916 – 18 September 2003) was a Jewish philosopher and Reform rabbi. Born in Halle, Germany, he was arrested by Nazis on the night of 9 November 1938, known as Kristallnacht. Briefly interned at the Sachsenhause ...
, the number of Commandments in Judaism should be 614 rather than the traditional 613. * 615 = 3 × 5 × 41,
sphenic number In number theory, a sphenic number (from grc, σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. Because there are infinitely many prime numbers, there are also infinitely many sphenic numbers. Definit ...
* 616 = 23 × 7 × 11,
Padovan number In number theory, the Padovan sequence is the sequence of integers ''P''(''n'') defined. by the initial values :P(0)=P(1)=P(2)=1, and the recurrence relation :P(n)=P(n-2)+P(n-3). The first few values of ''P''(''n'') are :1, 1, 1, 2, 2, 3, 4, 5 ...
, balanced number, an alternative value for the Number of the Beast (more commonly accepted to be
666 666 may refer to: * 666 (number) * 666 BC, a year * AD 666, a year * The number of the beast, a reference in the Book of Revelation in the New Testament Places * 666 Desdemona, a minor planet in the asteroid belt * U.S. Route 666, an America ...
). * 617 = prime number, sum of five consecutive primes (109 + 113 + 127 + 131 + 137),
Chen prime A prime number ''p'' is called a Chen prime if ''p'' + 2 is either a prime or a product of two primes (also called a semiprime). The even number 2''p'' + 2 therefore satisfies Chen's theorem. The Chen primes are named after Chen Jingru ...
,
Eisenstein prime In mathematics, an Eisenstein prime is an Eisenstein integer : z = a + b\,\omega, \quad \text \quad \omega = e^, that is irreducible (or equivalently prime) in the ring-theoretic sense: its only Eisenstein divisors are the units , itself ...
with no imaginary part, number of compositions of 17 into distinct parts, prime index prime, index of prime Lucas number **
Area code 617 Area codes 617 and 857 are the North American area codes serving Boston and several surrounding communities in Massachusetts—such as Brookline, Cambridge, Newton and Quincy ( LATA code 128). The main area code, 617, was one of the orig ...
, a telephone area code covering the metropolitan Boston area. * 618 = 2 × 3 × 103,
sphenic number In number theory, a sphenic number (from grc, σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. Because there are infinitely many prime numbers, there are also infinitely many sphenic numbers. Definit ...
, admirable number. * 619 = prime number, strobogrammatic prime, alternating factorial


620s

* 620 = 22 × 5 × 31, sum of four consecutive primes (149 + 151 + 157 + 163), sum of eight consecutive primes (61 + 67 + 71 + 73 + 79 + 83 + 89 + 97). The sum of the first 620 primes is itself prime. * 621 = 33 × 23, Harshad number, the discriminant of a totally real cubic field * 622 = 2 × 311,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, Fine number. Fine's sequence (or Fine numbers): number of relations of valence >= 1 on an n-set; also number of ordered rooted trees with n edges having root of even degree It is also the standard diameter of modern road bicycle wheels (622 mm, from hook bead to hook bead) * 623 = 7 × 89, number of partitions of 23 into an even number of parts * 624 = 24 × 3 × 13 = J4(5), sum of a twin prime (311 + 313), Harshad number, Zuckerman number * 625 = 252 = 54, sum of seven consecutive primes (73 + 79 + 83 + 89 + 97 + 101 + 103),
centered octagonal number A centered octagonal number is a centered figurate number that represents an octagon with a dot in the center and all other dots surrounding the center dot in successive octagonal layers.. The centered octagonal numbers are the same as the od ...
, 1-
automorphic number In mathematics, an automorphic number (sometimes referred to as a circular number) is a natural number in a given number base b whose square "ends" in the same digits as the number itself. Definition and properties Given a number base b, a natura ...
,
Friedman number A Friedman number is an integer, which represented in a given numeral system, is the result of a non-trivial expression using all its own digits in combination with any of the four basic arithmetic operators (+, −, ×, ÷), additive inverses, pa ...
since 625 = 56−2 * 626 = 2 × 313,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, 2-Knödel number. Stitch (Lilo & Stitch), Stitch's experiment number. * 627 = 3 × 11 × 19, sphenic number, number of integer partition (number theory), partitions of 20, Smith number * 628 = 22 × 157,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, totient sum for first 45 integers * 629 = 17 × 37, highly cototient number, Harshad number, number of diagonals in a 37-gon


630s

* 630 = 2 × 32 × 5 × 7, sum of six consecutive primes (97 + 101 + 103 + 107 + 109 + 113), triangular number, hexagonal number, sparsely totient number, Harshad number, balanced number * 631 = Cuban prime number, centered triangular number, centered hexagonal number, Chen prime, lazy caterer number * 632 = 23 × 79, refactorable number, number of 13-bead necklaces with 2 colors * 633 = 3 × 211, sum of three consecutive primes (199 + 211 + 223), Blum integer; also, in the title of the movie ''633 Squadron'' * 634 = 2 × 317,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, Smith number * 635 = 5 × 127, sum of nine consecutive primes (53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89), Mertens function(635) = 0, number of compositions of 13 into pairwise relatively prime parts ** "Project 635", the Irtysh River diversion project in China involving a Project 635 Dam, dam and a Irtysh–Karamay–Ürümqi Canal, canal. * 636 = 22 × 3 × 53, sum of ten consecutive primes (43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83), Smith number, Mertens function(636) = 0 * 637 = 72 × 13, Mertens function(637) = 0, decagonal number * 638 = 2 × 11 × 29, sphenic number, sum of four consecutive primes (151 + 157 + 163 + 167),
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, centered heptagonal number * 639 = 32 × 71, sum of the first twenty primes, also ISO 639 is the International Organization for Standardization, ISO's standard for codes for the representation of languages


640s

* 640 = 27 × 5, Harshad number, refactorable number, hexadecagonal number, number of 1's in all partitions of 24 into odd parts, number of acres in a square mile * 641 = prime number, Sophie Germain prime, factor of 4294967297 (number), 4294967297 (the smallest nonprime Fermat number), Chen prime, Eisenstein prime with no imaginary part, Proth prime * 642 = 2 × 3 × 107 = 14 + 24 + 54,
sphenic number In number theory, a sphenic number (from grc, σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. Because there are infinitely many prime numbers, there are also infinitely many sphenic numbers. Definit ...
, admirable number * 643 = prime number, largest prime factor of 123456 * 644 = 22 × 7 × 23,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, Perrin number, Harshad number, common umask, admirable number * 645 = 3 × 5 × 43, sphenic number, octagonal number, Smith number, Fermat pseudoprime to base 2, Harshad number * 646 = 2 × 17 × 19, sphenic number, also ISO 646 is the ISO's standard for international 7-bit variants of ASCII, number of permutations of length 7 without rising or falling successions * 647 = prime number, sum of five consecutive primes (113 + 127 + 131 + 137 + 139), Chen prime, Eisenstein prime with no imaginary part, 3647 - 2647 is prime * 648 = 23 × 34
A331452(7, 1)
Harshad number, Achilles number, area of a square with diagonal 36 * 649 = 11 × 59, Blum integer


650s

* 650 = 2 × 52 × 13, primitive abundant number, square pyramidal number, pronic number,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, totient sum for first 46 integers; (other fields) the number of seats in the House of Commons of the United Kingdom, admirable number * 651 = 3 × 7 × 31, sphenic number, pentagonal number, nonagonal number * 652 = 22 × 163, maximal number of regions by drawing 26 circles * 653 = prime number, Sophie Germain prime, balanced prime, Chen prime, Eisenstein prime with no imaginary part * 654 = 2 × 3 × 109, sphenic number,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, Smith number, admirable number * 655 = 5 × 131, number of toothpicks after 20 stages in a three-dimensional grid * 656 = 24 × 41 = \lfloor \frac \rfloor. In
Judaism Judaism ( he, ''Yahăḏūṯ'') is an Abrahamic, monotheistic, and ethnic religion comprising the collective religious, cultural, and legal tradition and civilization of the Jewish people. It has its roots as an organized religion in t ...
, 656 is the number of times that Jerusalem is mentioned in the Hebrew Bible or Old Testament. * 657 = 32 × 73, the largest known number not of the form ''a''2+''s'' with ''s'' a semiprime * 658 = 2 × 7 × 47,
sphenic number In number theory, a sphenic number (from grc, σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. Because there are infinitely many prime numbers, there are also infinitely many sphenic numbers. Definit ...
, untouchable number * 659 = prime number, Sophie Germain prime, sum of seven consecutive primes (79 + 83 + 89 + 97 + 101 + 103 + 107), Chen prime, Mertens function sets new low of −10 which stands until 661, highly cototient number, Eisenstein prime with no imaginary part, strictly non-palindromic number


660s

* 660 = 22 × 3 × 5 × 11 **Sum of four consecutive primes (157 + 163 + 167 + 173). **Sum of six consecutive primes (101 + 103 + 107 + 109 + 113 + 127). **Sum of eight consecutive primes (67 + 71 + 73 + 79 + 83 + 89 + 97 + 101). **Sparsely totient number. **Sum of 11th row when writing the natural numbers as a triangle. ** Harshad number. * 661 = prime number **Sum of three consecutive primes (211 + 223 + 227). **Mertens function sets new low of −11 which stands until 665. **Pentagram number of the form 5n^-5n+1. **Hexagram number of the form 6n^-6n+1 i.e. a star number. * 662 = 2 × 331,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, member of Mian–Chowla sequence * 663 = 3 × 13 × 17,
sphenic number In number theory, a sphenic number (from grc, σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. Because there are infinitely many prime numbers, there are also infinitely many sphenic numbers. Definit ...
, Smith number * 664 = 23 × 83, refactorable number, number of knapsack partitions of 33 **Telephone area code 664, area code for Montserrat. **Area code 664 (Mexico), Area code for Tijuana within Mexico. **Model number for the Amstrad CPC664 home computer. * 665 = 5 × 7 × 19,
sphenic number In number theory, a sphenic number (from grc, σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. Because there are infinitely many prime numbers, there are also infinitely many sphenic numbers. Definit ...
, Mertens function sets new low of −12 which stands until 1105, number of diagonals in a 38-gon *
666 666 may refer to: * 666 (number) * 666 BC, a year * AD 666, a year * The number of the beast, a reference in the Book of Revelation in the New Testament Places * 666 Desdemona, a minor planet in the asteroid belt * U.S. Route 666, an America ...
= 2 × 32 × 37, repdigit * 667 = 23 × 29, lazy caterer number * 668 = 22 × 167,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
* 669 = 3 × 223, blum integer


670s

* 670 = 2 × 5 × 67, sphenic number, octahedral number,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
* 671 = 11 × 61. This number is the magic constant of ''n''×''n'' normal magic square and Eight queens puzzle, ''n''-queens problem for ''n'' = 11. * 672 = 25 × 3 × 7, harmonic divisor number, Zuckerman number, admirable number * 673 = prime number, Proth prime * 674 = 2 × 337,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, 2-Knödel number * 675 = 33 × 52, Achilles number * 676 = 22 × 132 = 262, palindromic square * 677 = prime number, Chen prime, Eisenstein prime with no imaginary part, number of non-isomorphic self-dual multiset partitions of weight 10 * 678 = 2 × 3 × 113, sphenic number,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, number of surface points of an octahedron with side length 13, admirable number * 679 = 7 × 97, sum of three consecutive primes (223 + 227 + 229), sum of nine consecutive primes (59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 + 97), smallest number of multiplicative persistence 5


680s

* 680 = 23 × 5 × 17, tetrahedral number,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
* 681 = 3 × 227, centered pentagonal number * 682 = 2 × 11 × 31, sphenic number, sum of four consecutive primes (163 + 167 + 173 + 179), sum of ten consecutive primes (47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89), number of moves to solve the Norwegian puzzl
strikketoy
* 683 = prime number, Sophie Germain prime, sum of five consecutive primes (127 + 131 + 137 + 139 + 149), Chen prime, Eisenstein prime with no imaginary part, Wagstaff prime * 684 = 22 × 32 × 19, Harshad number, number of graphical forest partitions of 32 * 685 = 5 × 137, centered square number * 686 = 2 × 73,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, number of multigraphs on infinite set of nodes with 7 edges * 687 = 3 × 229, 687 days to orbit the sun (Mars) Knödel number, D-number * 688 = 24 × 43, Friedman number since 688 = 8 × 86, 2-
automorphic number In mathematics, an automorphic number (sometimes referred to as a circular number) is a natural number in a given number base b whose square "ends" in the same digits as the number itself. Definition and properties Given a number base b, a natura ...
* 689 = 13 × 53, sum of three consecutive primes (227 + 229 + 233), sum of seven consecutive primes (83 + 89 + 97 + 101 + 103 + 107 + 109). Strobogrammatic number


690s

* 690 = 2 × 3 × 5 × 23, sum of six consecutive primes (103 + 107 + 109 + 113 + 127 + 131), sparsely totient number, Smith number, Harshad number ** ISO 690 is the ISO's standard for bibliographic references * 691 = prime number, (negative) numerator of the Bernoulli number ''B''12 = -691/2730. Ramanujan's tau function τ and the divisor function σ11 are related by the remarkable congruence τ(''n'') ≡ σ11(''n'') (mod 691). ** In number theory, 691 is a "marker" (similar to the radioactive markers in biology): whenever it appears in a computation, one can be sure that Bernoulli numbers are involved. * 692 = 22 × 173, number of partitions of 48 into powers of 2 * 693 (number), 693 = 32 × 7 × 11, triangular matchstick number, the number of sections in Ludwig Wittgenstein's ''Philosophical Investigations''. * 694 = 2 × 347, centered triangular number,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
* 695 = 5 × 139, 695!! + 2 is prime. * 696 = 23 × 3 × 29, sum of eight consecutive primes (71 + 73 + 79 + 83 + 89 + 97 + 101 + 103), totient sum for first 47 integers, trails of length 9 on honeycomb lattice * 697 = 17 × 41, cake number; the number of sides of Colorado * 698 = 2 × 349,
nontotient In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotien ...
, sum of squares of two primes * 699 = 3 × 233, Knödel number, D-number


References

{{Integers, 6 Integers