21656122600 has 96 divisors (see below), whose sum is σ = 59399769600. Its totient is φ = 7185427200.

The previous prime is 21656122597. The next prime is 21656122601. The reversal of 21656122600 is 622165612.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is not an unprimeable number, because it can be changed into a prime (21656122601) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 206095 + ... + 292894.

It is an arithmetic number, because the mean of its divisors is an integer number (618747600).

Almost surely, 2^21656122600 is an apocalyptic number.

21656122600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21656122600 is an abundant number, since it is smaller than the sum of its proper divisors (37743647000).

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

21656122600 is a wasteful number, since it uses less digits than its factorization.

21656122600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 499043 (or 499034 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The spelling of 21656122600 in words is "twenty-one billion, six hundred fifty-six million, one hundred twenty-two thousand, six hundred".