199 (one hundred
ndninety-nine) is the
natural number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive in ...
following
198
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Year 198 (CXCVIII) was a common year starting on Sunday of the Julian calendar. At the time, it was known as the Year of the Consulship of Sergius and Gallus (or, less frequently, year 951 ''Ab urbe condita''). The denomination 198 fo ...
and preceding
200.
In mathematics
199 is a
centered triangular number
A centered (or centred) triangular number is a centered figurate number that represents an equilateral triangle with a dot in the center and all its other dots surrounding the center in successive equilateral triangular layers.
This is also t ...
.
It is a
prime number
A prime number (or a prime) is a natural number greater than 1 that is not a Product (mathematics), product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime ...
and the fourth part of a
prime quadruplet:
191,
193
Year 193 ( CXCIII) was a common year starting on Monday of the Julian calendar. At the time, it was known as the Year of the Consulship of Sosius and Ericius (or, less frequently, year 946 ''Ab urbe condita''). The denomination 193 for this ye ...
,
197, 199.
199 is the smallest natural number that takes more than two iterations to compute its
digital root
The digital root (also repeated digital sum) of a natural number in a given radix is the (single digit) value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit su ...
as a repeated digit sum:
Thus, its
additive persistence is three, and it is the smallest number of persistence three.
See also
*
References
Integers
{{Num-stub