21608256 has 28 divisors (see below), whose sum is σ = 57172352. Its totient is φ = 7202688.

The previous prime is 21608239. The next prime is 21608273. The reversal of 21608256 is 65280612.

It is an interprime number because it is at equal distance from previous prime (21608239) and next prime (21608273).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56080 + ... + 56463.

Almost surely, 2^21608256 is an apocalyptic number.

It is an amenable number.

21608256 is an abundant number, since it is smaller than the sum of its proper divisors (35564096).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21608256 is a wasteful number, since it uses less digits than its factorization.

21608256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112558 (or 112548 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 21608256 is about 4648.4681347730. The cubic root of 21608256 is about 278.5308078650.

Adding to 21608256 its reverse (65280612), we get a palindrome (86888868).

The spelling of 21608256 in words is "twenty-one million, six hundred eight thousand, two hundred fifty-six".