18031988 has 24 divisors (see below), whose sum is σ = 35773920. Its totient is φ = 7884000.

The previous prime is 18031957. The next prime is 18031991. The reversal of 18031988 is 88913081.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 8138 + ... + 10113.

It is an arithmetic number, because the mean of its divisors is an integer number (1490580).

Almost surely, 2^18031988 is an apocalyptic number.

It is an amenable number.

18031988 is a deficient number, since it is larger than the sum of its proper divisors (17741932).

18031988 is a wasteful number, since it uses less digits than its factorization.

18031988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18287 (or 18285 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 38.

The square root of 18031988 is about 4246.4088357105. The cubic root of 18031988 is about 262.2292925041.

The spelling of 18031988 in words is "eighteen million, thirty-one thousand, nine hundred eighty-eight".