21693937956 has 24 divisors (see below), whose sum is σ = 51696193920. Its totient is φ = 7077454752.

The previous prime is 21693937931. The next prime is 21693937963. The reversal of 21693937956 is 65973939612.

It is a self number, because there is not a number n which added to its sum of digits gives 21693937956.

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, 19231651 + ... + 19232778.

It is an arithmetic number, because the mean of its divisors is an integer number (2154008080).

Almost surely, 2^21693937956 is an apocalyptic number.

It is an amenable number.

21693937956 is an abundant number, since it is smaller than the sum of its proper divisors (30002255964).

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

21693937956 is a wasteful number, since it uses less digits than its factorization.

21693937956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38464483 (or 38464481 counting only the distinct ones).

The product of its digits is 16533720, while the sum is 60.

The spelling of 21693937956 in words is "twenty-one billion, six hundred ninety-three million, nine hundred thirty-seven thousand, nine hundred fifty-six".