Sixty three
63 is an odd number.
63 is a Harshad number, which means it is divisible by the sum of its digits (6 + 3 = 9, and 63 is divisible by 9).
In binary, 63 is represented as 111111.
In hex, 63 is represented as 3f.
Prime factorization of 63: 32 * 7.