21656236384 has 24 divisors (see below), whose sum is σ = 42918080688. Its totient is φ = 10756406400.

The previous prime is 21656236379. The next prime is 21656236391. The reversal of 21656236384 is 48363265612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2236087 + ... + 2245750.

It is an arithmetic number, because the mean of its divisors is an integer number (1788253362).

Almost surely, 2^21656236384 is an apocalyptic number.

It is an amenable number.

21656236384 is a deficient number, since it is larger than the sum of its proper divisors (21261844304).

21656236384 is a wasteful number, since it uses less digits than its factorization.

21656236384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4481998 (or 4481990 counting only the distinct ones).

The product of its digits is 1244160, while the sum is 46.

The spelling of 21656236384 in words is "twenty-one billion, six hundred fifty-six million, two hundred thirty-six thousand, three hundred eighty-four".