18518218 has 4 divisors (see below), whose sum is σ = 27777330. Its totient is φ = 9259108.

The previous prime is 18518209. The next prime is 18518231. The reversal of 18518218 is 81281581.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12981609 + 5536609 = 3603^2 + 2353^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4629553 + ... + 4629556.

Almost surely, 2^18518218 is an apocalyptic number.

18518218 is a deficient number, since it is larger than the sum of its proper divisors (9259112).

18518218 is an equidigital number, since it uses as much as digits as its factorization.

18518218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9259111.

The product of its digits is 5120, while the sum is 34.

The square root of 18518218 is about 4303.2799118812. The cubic root of 18518218 is about 264.5654108567.

Adding to 18518218 its reverse (81281581), we get a palindrome (99799799).

The spelling of 18518218 in words is "eighteen million, five hundred eighteen thousand, two hundred eighteen".