21307864844 has 12 divisors (see below), whose sum is σ = 42615729744. Its totient is φ = 9131942064.

The previous prime is 21307864841. The next prime is 21307864901. The reversal of 21307864844 is 44846870312.

21307864844 is an admirable number.

It is a super-2 number, since 2×21307864844² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21307864841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 380497559 + ... + 380497614.

It is an arithmetic number, because the mean of its divisors is an integer number (3551310812).

Almost surely, 2^21307864844 is an apocalyptic number.

It is an amenable number.

21307864844 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21307864844 is a wasteful number, since it uses less digits than its factorization.

21307864844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 760995184 (or 760995182 counting only the distinct ones).

The product of its (nonzero) digits is 1032192, while the sum is 47.

The spelling of 21307864844 in words is "twenty-one billion, three hundred seven million, eight hundred sixty-four thousand, eight hundred forty-four".