21656005512 has 32 divisors (see below), whose sum is σ = 54163824000. Its totient is φ = 7215493824.

The previous prime is 21656005477. The next prime is 21656005549. The reversal of 21656005512 is 21550065612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 142387 + ... + 252162.

It is an arithmetic number, because the mean of its divisors is an integer number (1692619500).

Almost surely, 2^21656005512 is an apocalyptic number.

It is an amenable number.

21656005512 is an abundant number, since it is smaller than the sum of its proper divisors (32507818488).

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

21656005512 is a wasteful number, since it uses less digits than its factorization.

21656005512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396845 (or 396841 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 33.

The spelling of 21656005512 in words is "twenty-one billion, six hundred fifty-six million, five thousand, five hundred twelve".