18651972920 has 64 divisors (see below), whose sum is σ = 49616107200. Its totient is φ = 6174443520.

The previous prime is 18651972919. The next prime is 18651972923. The reversal of 18651972920 is 2927915681.

It is a hoax number, since the sum of its digits (50) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18651972923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1140401 + ... + 1156640.

It is an arithmetic number, because the mean of its divisors is an integer number (775251675).

Almost surely, 2^18651972920 is an apocalyptic number.

18651972920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18651972920 is an abundant number, since it is smaller than the sum of its proper divisors (30964134280).

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

18651972920 is a wasteful number, since it uses less digits than its factorization.

18651972920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2297088 (or 2297084 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 50.

The spelling of 18651972920 in words is "eighteen billion, six hundred fifty-one million, nine hundred seventy-two thousand, nine hundred twenty".