21307764764 has 24 divisors (see below), whose sum is σ = 43807573488. Its totient is φ = 8940320640.

The previous prime is 21307764763. The next prime is 21307764767. The reversal of 21307764764 is 46746770312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21307764763) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18625097 + ... + 18626240.

It is an arithmetic number, because the mean of its divisors is an integer number (1825315562).

Almost surely, 2^21307764764 is an apocalyptic number.

It is an amenable number.

21307764764 is an abundant number, since it is smaller than the sum of its proper divisors (22499808724).

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

21307764764 is a wasteful number, since it uses less digits than its factorization.

21307764764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37251365 (or 37251363 counting only the distinct ones).

The product of its (nonzero) digits is 1185408, while the sum is 47.

The spelling of 21307764764 in words is "twenty-one billion, three hundred seven million, seven hundred sixty-four thousand, seven hundred sixty-four".