18355218 has 32 divisors (see below), whose sum is σ = 42372096. Its totient is φ = 5192208.

The previous prime is 18355199. The next prime is 18355229. The reversal of 18355218 is 81255381.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2205 + ... + 6447.

It is an arithmetic number, because the mean of its divisors is an integer number (1324128).

Almost surely, 2^18355218 is an apocalyptic number.

18355218 is an abundant number, since it is smaller than the sum of its proper divisors (24016878).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18355218 is a wasteful number, since it uses less digits than its factorization.

18355218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4358.

The product of its digits is 9600, while the sum is 33.

The square root of 18355218 is about 4284.2990091729. The cubic root of 18355218 is about 263.7868745940.

The spelling of 18355218 in words is "eighteen million, three hundred fifty-five thousand, two hundred eighteen".