18616631 has 4 divisors (see below), whose sum is σ = 20309064. Its totient is φ = 16924200.

The previous prime is 18616627. The next prime is 18616657. The reversal of 18616631 is 13661681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13661681 = 11 ⋅1241971.

It is a cyclic number.

It is not a de Polignac number, because 18616631 - 2² = 18616627 is a prime.

It is a super-2 number, since 2×18616631² = 693157899580322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18616601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 846200 + ... + 846221.

It is an arithmetic number, because the mean of its divisors is an integer number (5077266).

Almost surely, 2^18616631 is an apocalyptic number.

18616631 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18616631 is a deficient number, since it is larger than the sum of its proper divisors (1692433).

18616631 is a wasteful number, since it uses less digits than its factorization.

18616631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1692432.

The product of its digits is 5184, while the sum is 32.

The square root of 18616631 is about 4314.6994101559. The cubic root of 18616631 is about 265.0332508413.

The spelling of 18616631 in words is "eighteen million, six hundred sixteen thousand, six hundred thirty-one".