21591000936 has 96 divisors (see below), whose sum is σ = 58968000000. Its totient is φ = 7136664192.

The previous prime is 21591000919. The next prime is 21591000967. The reversal of 21591000936 is 63900019512.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21591000936.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4316565 + ... + 4321563.

It is an arithmetic number, because the mean of its divisors is an integer number (614250000).

Almost surely, 2^21591000936 is an apocalyptic number.

It is an amenable number.

21591000936 is an abundant number, since it is smaller than the sum of its proper divisors (37376999064).

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

21591000936 is a wasteful number, since it uses less digits than its factorization.

21591000936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5503 (or 5496 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The spelling of 21591000936 in words is "twenty-one billion, five hundred ninety-one million, nine hundred thirty-six", and thus it is an aban number.