18668687 has 2 divisors, whose sum is σ = 18668688. Its totient is φ = 18668686.

The previous prime is 18668641. The next prime is 18668693. The reversal of 18668687 is 78686681.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18668687 - 2²⁰ = 17620111 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18662687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9334343 + 9334344.

It is an arithmetic number, because the mean of its divisors is an integer number (9334344).

Almost surely, 2^18668687 is an apocalyptic number.

18668687 is a deficient number, since it is larger than the sum of its proper divisors (1).

18668687 is an equidigital number, since it uses as much as digits as its factorization.

18668687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 774144, while the sum is 50.

The square root of 18668687 is about 4320.7276007636. The cubic root of 18668687 is about 265.2800504454.

The spelling of 18668687 in words is "eighteen million, six hundred sixty-eight thousand, six hundred eighty-seven".