One hundred (100, C) is the natural number following ninety-nine and preceding one hundred one. The square of 10, it is a composite number, with its divisors being 2, 4, 5, 10, 20, 40 and 50, and its factorization is

This number is the sum of the first nine prime numbers, as well as the sum of two prime numbers (47 + 53). But perhaps this number is most important as the basis of percentages (literally "per hundred"), with 100% being a full amount.

One hundred is also:

See also: hundred
See also: ninety, one hundred, one hundred and ten

This article is about the number. For the year AD 100, see 100.