18686918 has 16 divisors (see below), whose sum is σ = 30136320. Its totient is φ = 8662536.

The previous prime is 18686911. The next prime is 18686947. The reversal of 18686918 is 81968681.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18686911) 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, 3446 + ... + 7017.

It is an arithmetic number, because the mean of its divisors is an integer number (1883520).

Almost surely, 2^18686918 is an apocalyptic number.

18686918 is a deficient number, since it is larger than the sum of its proper divisors (11449402).

18686918 is a wasteful number, since it uses less digits than its factorization.

18686918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10531.

The product of its digits is 165888, while the sum is 47.

The square root of 18686918 is about 4322.8368000654. The cubic root of 18686918 is about 265.3663758726.

The spelling of 18686918 in words is "eighteen million, six hundred eighty-six thousand, nine hundred eighteen".