21630021664 has 48 divisors (see below), whose sum is σ = 45127053720. Its totient is φ = 10187376640.

The previous prime is 21630021641. The next prime is 21630021709. The reversal of 21630021664 is 46612003612.

It can be written as a sum of positive squares in 4 ways, for example, as 14230581264 + 7399440400 = 119292^2 + 86020^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 246199 + ... + 322294.

Almost surely, 2^21630021664 is an apocalyptic number.

It is an amenable number.

21630021664 is an abundant number, since it is smaller than the sum of its proper divisors (23497032056).

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

21630021664 is a wasteful number, since it uses less digits than its factorization.

21630021664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568573 (or 568565 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 31.

The spelling of 21630021664 in words is "twenty-one billion, six hundred thirty million, twenty-one thousand, six hundred sixty-four".