21616564002664 has 16 divisors (see below), whose sum is σ = 42915237358500. Its totient is φ = 10172500707072.

The previous prime is 21616564002641. The next prime is 21616564002689. The reversal of 21616564002664 is 46620046561612.

It can be written as a sum of positive squares in 2 ways, for example, as 21499524750564 + 117039252100 = 4636758^2 + 342110^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79472661639 + ... + 79472661910.

Almost surely, 2^{21616564002664} is an apocalyptic number.

It is an amenable number.

21616564002664 is a deficient number, since it is larger than the sum of its proper divisors (21298673355836).

21616564002664 is a wasteful number, since it uses less digits than its factorization.

21616564002664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158945323572 (or 158945323568 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 49.

The spelling of 21616564002664 in words is "twenty-one trillion, six hundred sixteen billion, five hundred sixty-four million, two thousand, six hundred sixty-four".