Ninety
90 is an even number.
90 is a Harshad number, which means it is divisible by the sum of its digits (9 + 0 = 9, and 90 is divisible by 9).
In binary, 90 is represented as 1011010.
In hex, 90 is represented as 5a.
Prime factorization of 90: 2 * 32 * 5.
Factors of 90 are: 1, 2, 3, 5, 6, 9, 9, 10, 15, 18, 30, 45, 90.