21642165400252 has 72 divisors (see below), whose sum is σ = 41497439662224. Its totient is φ = 9866756671488.

The previous prime is 21642165400153. The next prime is 21642165400307. The reversal of 21642165400252 is 25200456124612.

It is a super-2 number, since 2×21642165400252² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8880063 + ... + 11051689.

It is an arithmetic number, because the mean of its divisors is an integer number (576353328642).

Almost surely, 2^{21642165400252} is an apocalyptic number.

It is an amenable number.

21642165400252 is a deficient number, since it is larger than the sum of its proper divisors (19855274261972).

21642165400252 is a wasteful number, since it uses less digits than its factorization.

21642165400252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2171935 (or 2171916 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 40.

The spelling of 21642165400252 in words is "twenty-one trillion, six hundred forty-two billion, one hundred sixty-five million, four hundred thousand, two hundred fifty-two".