21656691392 has 28 divisors (see below), whose sum is σ = 49114283280. Its totient is φ = 9281438976.

The previous prime is 21656691377. The next prime is 21656691401. The reversal of 21656691392 is 29319665612.

It is a tau number, because it is divible by the number of its divisors (28).

It is a self number, because there is not a number n which added to its sum of digits gives 21656691392.

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, 24169967 + ... + 24170862.

Almost surely, 2^21656691392 is an apocalyptic number.

It is an amenable number.

21656691392 is an abundant number, since it is smaller than the sum of its proper divisors (27457591888).

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

21656691392 is an equidigital number, since it uses as much as digits as its factorization.

21656691392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48340848 (or 48340838 counting only the distinct ones).

The product of its digits is 1049760, while the sum is 50.

The spelling of 21656691392 in words is "twenty-one billion, six hundred fifty-six million, six hundred ninety-one thousand, three hundred ninety-two".