18117631 has 8 divisors (see below), whose sum is σ = 21924000. Its totient is φ = 14615808.

The previous prime is 18117611. The next prime is 18117647. The reversal of 18117631 is 13671181.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18117631 - 2⁷ = 18117503 is a prime.

It is a super-2 number, since 2×18117631² = 656497106104322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18117631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18117601) 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, 76006 + ... + 76243.

It is an arithmetic number, because the mean of its divisors is an integer number (2740500).

Almost surely, 2^18117631 is an apocalyptic number.

18117631 is a deficient number, since it is larger than the sum of its proper divisors (3806369).

18117631 is a wasteful number, since it uses less digits than its factorization.

18117631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152273.

The product of its digits is 1008, while the sum is 28.

The square root of 18117631 is about 4256.4810583392. The cubic root of 18117631 is about 262.6437900046.

It can be divided in two parts, 18 and 117631, that added together give a 6-th power (117649 = 7⁶).

The spelling of 18117631 in words is "eighteen million, one hundred seventeen thousand, six hundred thirty-one".