21686701908 has 24 divisors (see below), whose sum is σ = 51050115648. Its totient is φ = 7164927616.

The previous prime is 21686701901. The next prime is 21686701919. The reversal of 21686701908 is 80910768612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21686701901) 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, 7995216 + ... + 7997927.

It is an arithmetic number, because the mean of its divisors is an integer number (2127088152).

Almost surely, 2^21686701908 is an apocalyptic number.

It is an amenable number.

21686701908 is an abundant number, since it is smaller than the sum of its proper divisors (29363413740).

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

21686701908 is a wasteful number, since it uses less digits than its factorization.

21686701908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15993263 (or 15993261 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 48.

It can be divided in two parts, 2168 and 6701908, that added together give a palindrome (6704076).

The spelling of 21686701908 in words is "twenty-one billion, six hundred eighty-six million, seven hundred one thousand, nine hundred eight".