21686868372 has 24 divisors (see below), whose sum is σ = 54495208096. Its totient is φ = 6672882528.

The previous prime is 21686868367. The next prime is 21686868373. The reversal of 21686868372 is 27386868612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21686868373) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69509038 + ... + 69509349.

Almost surely, 2^21686868372 is an apocalyptic number.

It is an amenable number.

21686868372 is an abundant number, since it is smaller than the sum of its proper divisors (32808339724).

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

21686868372 is a wasteful number, since it uses less digits than its factorization.

21686868372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139018407 (or 139018405 counting only the distinct ones).

The product of its digits is 9289728, while the sum is 57.

The spelling of 21686868372 in words is "twenty-one billion, six hundred eighty-six million, eight hundred sixty-eight thousand, three hundred seventy-two".