18518999 has 2 divisors, whose sum is σ = 18519000. Its totient is φ = 18518998.

The previous prime is 18518993. The next prime is 18519019. The reversal of 18518999 is 99981581.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18518999 - 2²⁰ = 17470423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18518993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9259499 + 9259500.

It is an arithmetic number, because the mean of its divisors is an integer number (9259500).

Almost surely, 2^18518999 is an apocalyptic number.

18518999 is a deficient number, since it is larger than the sum of its proper divisors (1).

18518999 is an equidigital number, since it uses as much as digits as its factorization.

18518999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 233280, while the sum is 50.

The square root of 18518999 is about 4303.3706556605. The cubic root of 18518999 is about 264.5691301253.

The spelling of 18518999 in words is "eighteen million, five hundred eighteen thousand, nine hundred ninety-nine".