21979694156 has 24 divisors (see below), whose sum is σ = 45147482016. Its totient is φ = 9165277440.

The previous prime is 21979694137. The next prime is 21979694201. The reversal of 21979694156 is 65149697912.

It is a junction number, because it is equal to n+sod(n) for n = 21979694095 and 21979694104.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10606925 + ... + 10608996.

It is an arithmetic number, because the mean of its divisors is an integer number (1881145084).

Almost surely, 2^21979694156 is an apocalyptic number.

It is an amenable number.

21979694156 is an abundant number, since it is smaller than the sum of its proper divisors (23167787860).

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

21979694156 is a wasteful number, since it uses less digits than its factorization.

21979694156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21215969 (or 21215967 counting only the distinct ones).

The product of its digits is 7348320, while the sum is 59.

The spelling of 21979694156 in words is "twenty-one billion, nine hundred seventy-nine million, six hundred ninety-four thousand, one hundred fifty-six".