Four thousand nine hundred ninety one
4991 is an odd number.
4991 is a Harshad number, which means it is divisible by the sum of its digits (4 + 9 + 9 + 1 = 23, and 4991 is divisible by 23).
In binary, 4991 is represented as 1001101111111.
In hex, 4991 is represented as 137f.
Prime factorization of 4991: 7 * 23 * 31.