18638972 has 36 divisors (see below), whose sum is σ = 36889944. Its totient is φ = 8166240.

The previous prime is 18638959. The next prime is 18638989. The reversal of 18638972 is 27983681.

It is a super-2 number, since 2×18638972² = 694822554433568, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 174143 + ... + 174249.

Almost surely, 2^18638972 is an apocalyptic number.

It is an amenable number.

18638972 is a deficient number, since it is larger than the sum of its proper divisors (18250972).

18638972 is a wasteful number, since it uses less digits than its factorization.

18638972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266 (or 157 counting only the distinct ones).

The product of its digits is 145152, while the sum is 44.

The square root of 18638972 is about 4317.2875743921. The cubic root of 18638972 is about 265.1392267092.

The spelling of 18638972 in words is "eighteen million, six hundred thirty-eight thousand, nine hundred seventy-two".