21560728904 has 64 divisors (see below), whose sum is σ = 49026055680. Its totient is φ = 8754624000.

The previous prime is 21560728801. The next prime is 21560728961. The reversal of 21560728904 is 40982706512.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (44).

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, 268517 + ... + 339444.

It is an arithmetic number, because the mean of its divisors is an integer number (766032120).

Almost surely, 2^21560728904 is an apocalyptic number.

It is an amenable number.

21560728904 is an abundant number, since it is smaller than the sum of its proper divisors (27465326776).

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

21560728904 is a wasteful number, since it uses less digits than its factorization.

21560728904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608022 (or 608018 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 44.

The spelling of 21560728904 in words is "twenty-one billion, five hundred sixty million, seven hundred twenty-eight thousand, nine hundred four".