18668513 has 2 divisors, whose sum is σ = 18668514. Its totient is φ = 18668512.

The previous prime is 18668497. The next prime is 18668549. The reversal of 18668513 is 31586681.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18464209 + 204304 = 4297^2 + 452^2 .

It is a cyclic number.

It is not a de Polignac number, because 18668513 - 2⁴ = 18668497 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18668213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9334256 + 9334257.

It is an arithmetic number, because the mean of its divisors is an integer number (9334257).

Almost surely, 2^18668513 is an apocalyptic number.

It is an amenable number.

18668513 is a deficient number, since it is larger than the sum of its proper divisors (1).

18668513 is an equidigital number, since it uses as much as digits as its factorization.

18668513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 38.

The square root of 18668513 is about 4320.7074652191. The cubic root of 18668513 is about 265.2792262690.

The spelling of 18668513 in words is "eighteen million, six hundred sixty-eight thousand, five hundred thirteen".