21610256 has 10 divisors (see below), whose sum is σ = 41869902. Its totient is φ = 10805120.

The previous prime is 21610241. The next prime is 21610279. The reversal of 21610256 is 65201612.

It can be written as a sum of positive squares in only one way, i.e., 21529600 + 80656 = 4640^2 + 284^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 675305 + ... + 675336.

Almost surely, 2^21610256 is an apocalyptic number.

It is an amenable number.

21610256 is a deficient number, since it is larger than the sum of its proper divisors (20259646).

21610256 is a wasteful number, since it uses less digits than its factorization.

21610256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1350649 (or 1350643 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21610256 is about 4648.6832544281. The cubic root of 21610256 is about 278.5394009452.

Adding to 21610256 its reverse (65201612), we get a palindrome (86811868).

The spelling of 21610256 in words is "twenty-one million, six hundred ten thousand, two hundred fifty-six".