21651566752 has 24 divisors (see below), whose sum is σ = 42635406996. Its totient is φ = 10823526912.

The previous prime is 21651566719. The next prime is 21651566773. The reversal of 21651566752 is 25766515612.

It can be written as a sum of positive squares in 2 ways, for example, as 21119064976 + 532501776 = 145324^2 + 23076^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 91108 + ... + 227164.

Almost surely, 2^21651566752 is an apocalyptic number.

It is an amenable number.

21651566752 is a deficient number, since it is larger than the sum of its proper divisors (20983840244).

21651566752 is a wasteful number, since it uses less digits than its factorization.

21651566752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141040 (or 141032 counting only the distinct ones).

The product of its digits is 756000, while the sum is 46.

The spelling of 21651566752 in words is "twenty-one billion, six hundred fifty-one million, five hundred sixty-six thousand, seven hundred fifty-two".