80 (eighty) is the
natural number following
79 and preceding
81.
In mathematics
80 is:
* the sum of
Euler's totient function φ(''x'') over the first sixteen integers.
* a
semiperfect number, since adding up some subsets of its divisors (e.g.,
1,
4,
5,
10,
20 and
40) gives 80.
* a
ménage number.
*
palindromic in bases 3 (2222
3), 6 (212
6), 9 (88
9), 15 (55
15), 19 (44
19) and 39 (22
39).
* a
repdigit in bases 3, 9, 15, 19 and 39.
The
Pareto principle (also known as the 80-20 rule) states that, for many events, roughly 80% of the effects come from 20% of the causes.
[.][.]
Every solvable configuration of the
15 puzzle can be solved in no more than 80 single-tile moves.
[A. Brüngger, A. Marzetta, K. Fukuda and J. Nievergelt]
The parallel search bench ZRAM and its applications
''Annals of Operations Research'' 90 (1999), pp. 45–63.
In science
* The
atomic number
The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei, this is equal to the proton number (''n''p) or the number of protons found in the nucleus of every ...
of
mercury
In religion
* According to Exodus 7:7, Moses was 80 years old when he initially spoke to Pharaoh on behalf of his people. Today, 80 years of age is the upper
age limit
This article gives an outline of age restrictions.
List
*Age of candidacy
*Age of consent
*Age requirements in gymnastics
*Age segregation
*Defense of infancy
*Legal drinking age
* Legal smoking age
*Legal working age
*List of countries by ...
for
cardinals to vote in
papal election
A papal conclave is a gathering of the College of Cardinals convened to elect a bishop of Rome, also known as the pope. Catholics consider the pope to be the apostolic successor of Saint Peter and the earthly head of the Catholic Church.
C ...
s.
In other fields
Eighty is also:
* used in the classic book title ''
Around the World in Eighty Days
''Around the World in Eighty Days'' (french: link=no, Le tour du monde en quatre-vingts jours) is an adventure novel by the French writer Jules Verne, first published in French in 1872. In the story, Phileas Fogg of London and his newly employ ...
''
* the length of the
Eighty Years' War
The Eighty Years' War or Dutch Revolt ( nl, Nederlandse Opstand) ( c.1566/1568–1648) was an armed conflict in the Habsburg Netherlands between disparate groups of rebels and the Spanish government. The causes of the war included the Refo ...
or Dutch revolt (1568–1648)
* the standard
TCP/IP
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...
port number for
HTTP
The Hypertext Transfer Protocol (HTTP) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, w ...
connections
* the 80A, 80B and 80C
photographic filters
In photography and cinematography, a filter is a camera accessory consisting of an optical filter that can be inserted into the optical path. The filter can be of a square or oblong shape and mounted in a holder accessory, or, more commonly, a g ...
correct for excessive redness under
tungsten lighting
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated until it glows. The filament is enclosed in a glass bulb with a vacuum or inert gas to protect the filament from oxida ...
* The year
AD 80
__NOTOC__
AD 80 ( LXXX) was a leap year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Domitianus (or, less frequently, year 833 ''Ab ur ...
,
80 BC, or 1980
*
Eighty shilling ale
* The older four-pin-base version of the
5Y3GT The 5Y3 is a medium-power directly heated full-wave rectifier vacuum tube introduced by RCA in 1935. It has found wide use in tube radios and early guitar amplifiers (of the Fender Champ type). It is virtually identical, electrically, to the ol ...
rectifier
A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The reverse operation (converting DC to AC) is performed by an inver ...
tube
Tube or tubes may refer to:
* ''Tube'' (2003 film), a 2003 Korean film
* ''The Tube'' (TV series), a music related TV series by Channel 4 in the United Kingdom
* "Tubes" (Peter Dale), performer on the Soccer AM television show
* Tube (band), a ...
* A common limit for the
characters per line
In typography and computing, characters per line (CPL) or terminal width refers to the maximal number of monospaced characters that may appear on a single line. It is similar to line length in typesetting.
History
The limit of the line length ...
, in computing, derived from the number of columns in
IBM cards
* American band
Green Day has a song called "
80"
* A fictional alien superhero named ''
Ultraman 80
is a Japanese tokusatsu TV show produced by Tsuburaya Productions which aired on the Tokyo Broadcasting System channel from April 2, 1980, to March 25, 1981, lasting a total of 50 episodes. After going off the air in 1981, the network still aired ...
''
* On the
Réaumur scale
__NOTOC__
The Réaumur scale (; °Ré, °Re, °r), also known as the "octogesimal division", is a temperature scale for which the melting and boiling points of water are defined as 0 and 80 degrees respectively. The scale is named for René A ...
, 80 degrees is the boiling temperature of pure
water at
sea level
See also
*
List of highways numbered 80
References
External links
*
wiktionary:eighty for ''80'' in other languages.
{{DEFAULTSORT:80 (Number)
Integers