18137866 has 4 divisors (see below), whose sum is σ = 27206802. Its totient is φ = 9068932.

The previous prime is 18137857. The next prime is 18137887. The reversal of 18137866 is 66873181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66873181 = 107 ⋅624983.

It can be written as a sum of positive squares in only one way, i.e., 15484225 + 2653641 = 3935^2 + 1629^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4534465 + ... + 4534468.

Almost surely, 2^18137866 is an apocalyptic number.

18137866 is a deficient number, since it is larger than the sum of its proper divisors (9068936).

18137866 is an equidigital number, since it uses as much as digits as its factorization.

18137866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9068935.

The product of its digits is 48384, while the sum is 40.

The square root of 18137866 is about 4258.8573584942. The cubic root of 18137866 is about 262.7415330953.

The spelling of 18137866 in words is "eighteen million, one hundred thirty-seven thousand, eight hundred sixty-six".