21656340576 has 96 divisors (see below), whose sum is σ = 68023156320. Its totient is φ = 6663485952.

The previous prime is 21656340569. The next prime is 21656340583. The reversal of 21656340576 is 67504365612.

21656340576 is a `hidden beast` number, since 2 + 1 + 6 + 5 + 634 + 0 + 5 + 7 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (21656340569) and next prime (21656340583).

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 952815 + ... + 975278.

It is an arithmetic number, because the mean of its divisors is an integer number (708574545).

Almost surely, 2^21656340576 is an apocalyptic number.

21656340576 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21656340576 is an abundant number, since it is smaller than the sum of its proper divisors (46366815744).

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

21656340576 is a wasteful number, since it uses less digits than its factorization.

21656340576 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1928125 (or 1928111 counting only the distinct ones).

The product of its (nonzero) digits is 907200, while the sum is 45.

The spelling of 21656340576 in words is "twenty-one billion, six hundred fifty-six million, three hundred forty thousand, five hundred seventy-six".