21656144604 has 24 divisors (see below), whose sum is σ = 51359382928. Its totient is φ = 7100375040.

The previous prime is 21656144597. The next prime is 21656144621. The reversal of 21656144604 is 40644165612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14791717 + ... + 14793180.

Almost surely, 2^21656144604 is an apocalyptic number.

It is an amenable number.

21656144604 is an abundant number, since it is smaller than the sum of its proper divisors (29703238324).

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

21656144604 is a wasteful number, since it uses less digits than its factorization.

21656144604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29584965 (or 29584963 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 39.

The spelling of 21656144604 in words is "twenty-one billion, six hundred fifty-six million, one hundred forty-four thousand, six hundred four".