21642296172 has 24 divisors (see below), whose sum is σ = 57712790016. Its totient is φ = 6183513168.

The previous prime is 21642296171. The next prime is 21642296173. The reversal of 21642296172 is 27169224612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21642296171) and next prime (21642296173).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (21642296171) 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, 128823108 + ... + 128823275.

It is an arithmetic number, because the mean of its divisors is an integer number (2404699584).

Almost surely, 2^21642296172 is an apocalyptic number.

It is an amenable number.

21642296172 is an abundant number, since it is smaller than the sum of its proper divisors (36070493844).

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

21642296172 is a wasteful number, since it uses less digits than its factorization.

21642296172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257646397 (or 257646395 counting only the distinct ones).

The product of its digits is 145152, while the sum is 42.

The spelling of 21642296172 in words is "twenty-one billion, six hundred forty-two million, two hundred ninety-six thousand, one hundred seventy-two".