21564307320788 has 12 divisors (see below), whose sum is σ = 37838710837620. Its totient is φ = 10753247081472.

The previous prime is 21564307320737. The next prime is 21564307320797. The reversal of 21564307320788 is 88702370346512.

It can be written as a sum of positive squares in 2 ways, for example, as 4431479691664 + 17132827629124 = 2105108^2 + 4139182^2 .

It is a super-4 number, since 4×21564307320788⁴ (a number of 54 digits) contains 4444 as substring.

It is a congruent number.

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, 7226643053 + ... + 7226646036.

It is an arithmetic number, because the mean of its divisors is an integer number (3153225903135).

Almost surely, 2^{21564307320788} is an apocalyptic number.

It is an amenable number.

21564307320788 is a deficient number, since it is larger than the sum of its proper divisors (16274403516832).

21564307320788 is a wasteful number, since it uses less digits than its factorization.

21564307320788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14453289466 (or 14453289464 counting only the distinct ones).

The product of its (nonzero) digits is 13547520, while the sum is 56.

The spelling of 21564307320788 in words is "twenty-one trillion, five hundred sixty-four billion, three hundred seven million, three hundred twenty thousand, seven hundred eighty-eight".