21515030656 has 32 divisors (see below), whose sum is σ = 48985116480. Its totient is φ = 9220727040.

The previous prime is 21515030633. The next prime is 21515030743. The reversal of 21515030656 is 65603051512.

It is a tau number, because it is divible by the number of its divisors (32).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12005260 + ... + 12007051.

It is an arithmetic number, because the mean of its divisors is an integer number (1530784890).

Almost surely, 2^21515030656 is an apocalyptic number.

It is an amenable number.

21515030656 is an abundant number, since it is smaller than the sum of its proper divisors (27470085824).

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

21515030656 is an equidigital number, since it uses as much as digits as its factorization.

21515030656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24012332 (or 24012320 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 34.

The spelling of 21515030656 in words is "twenty-one billion, five hundred fifteen million, thirty thousand, six hundred fifty-six".