18318531 has 16 divisors (see below), whose sum is σ = 30451968. Its totient is φ = 9516000.

The previous prime is 18318529. The next prime is 18318539. The reversal of 18318531 is 13581381.

It is not a de Polignac number, because 18318531 - 2¹ = 18318529 is a prime.

It is a super-2 number, since 2×18318531² = 671137155995922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18318539) 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 15 ways as a sum of consecutive naturals, for example, 39420 + ... + 39881.

It is an arithmetic number, because the mean of its divisors is an integer number (1903248).

Almost surely, 2^18318531 is an apocalyptic number.

18318531 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18318531 is a deficient number, since it is larger than the sum of its proper divisors (12133437).

18318531 is a wasteful number, since it uses less digits than its factorization.

18318531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79322.

The product of its digits is 2880, while the sum is 30.

The square root of 18318531 is about 4280.0153037110. The cubic root of 18318531 is about 263.6110117264.

The spelling of 18318531 in words is "eighteen million, three hundred eighteen thousand, five hundred thirty-one".