18397631 has 16 divisors (see below), whose sum is σ = 22080000. Its totient is φ = 14987808.

The previous prime is 18397627. The next prime is 18397637. The reversal of 18397631 is 13679381.

It is a cyclic number.

It is not a de Polignac number, because 18397631 - 2² = 18397627 is a prime.

It is a super-2 number, since 2×18397631² = 676945652824322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18397637) 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, 36620 + ... + 37118.

It is an arithmetic number, because the mean of its divisors is an integer number (1380000).

Almost surely, 2^18397631 is an apocalyptic number.

18397631 is a deficient number, since it is larger than the sum of its proper divisors (3682369).

18397631 is a wasteful number, since it uses less digits than its factorization.

18397631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 758.

The product of its digits is 27216, while the sum is 38.

The square root of 18397631 is about 4289.2459710303. The cubic root of 18397631 is about 263.9898938204.

The spelling of 18397631 in words is "eighteen million, three hundred ninety-seven thousand, six hundred thirty-one".