21656025636432 has 160 divisors (see below), whose sum is σ = 62042795090304. Its totient is φ = 6453636249600.

The previous prime is 21656025636359. The next prime is 21656025636461. The reversal of 21656025636432 is 23463652065612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 178919358 + ... + 179040354.

Almost surely, 2^{21656025636432} is an apocalyptic number.

21656025636432 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21656025636432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31021397545152).

21656025636432 is an abundant number, since it is smaller than the sum of its proper divisors (40386769453872).

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

21656025636432 is a wasteful number, since it uses less digits than its factorization.

21656025636432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126637 (or 126631 counting only the distinct ones).

The product of its (nonzero) digits is 9331200, while the sum is 51.

The spelling of 21656025636432 in words is "twenty-one trillion, six hundred fifty-six billion, twenty-five million, six hundred thirty-six thousand, four hundred thirty-two".