18311986 has 24 divisors (see below), whose sum is σ = 34859376. Its totient is φ = 7134120.

The previous prime is 18311983. The next prime is 18311987. The reversal of 18311986 is 68911381.

It is not an unprimeable number, because it can be changed into a prime (18311983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7416 + ... + 9571.

It is an arithmetic number, because the mean of its divisors is an integer number (1452474).

Almost surely, 2^18311986 is an apocalyptic number.

18311986 is a deficient number, since it is larger than the sum of its proper divisors (16547390).

18311986 is a wasteful number, since it uses less digits than its factorization.

18311986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17014 (or 17007 counting only the distinct ones).

The product of its digits is 10368, while the sum is 37.

The square root of 18311986 is about 4279.2506353332. The cubic root of 18311986 is about 263.5796129279.

The spelling of 18311986 in words is "eighteen million, three hundred eleven thousand, nine hundred eighty-six".