21056508 has 36 divisors (see below), whose sum is σ = 58066008. Its totient is φ = 6380640.

The previous prime is 21056507. The next prime is 21056527. The reversal of 21056508 is 80565012.

21056508 is a `hidden beast` number, since 2 + 1 + 0 + 5 + 650 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 26191 + ... + 26982.

Almost surely, 2^21056508 is an apocalyptic number.

It is an amenable number.

21056508 is an abundant number, since it is smaller than the sum of its proper divisors (37009500).

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

21056508 is a wasteful number, since it uses less digits than its factorization.

21056508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53194 (or 53189 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 21056508 is about 4588.7370811586. The cubic root of 21056508 is about 276.1396583683.

The spelling of 21056508 in words is "twenty-one million, fifty-six thousand, five hundred eight".