18218238 has 16 divisors (see below), whose sum is σ = 36981120. Its totient is φ = 5981976.

The previous prime is 18218209. The next prime is 18218257. The reversal of 18218238 is 83281281.

It is a junction number, because it is equal to n+sod(n) for n = 18218199 and 18218208.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22258 + ... + 23061.

It is an arithmetic number, because the mean of its divisors is an integer number (2311320).

Almost surely, 2^18218238 is an apocalyptic number.

18218238 is an abundant number, since it is smaller than the sum of its proper divisors (18762882).

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

18218238 is a wasteful number, since it uses less digits than its factorization.

18218238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45391.

The product of its digits is 6144, while the sum is 33.

The square root of 18218238 is about 4268.2827928805. The cubic root of 18218238 is about 263.1290455687.

The spelling of 18218238 in words is "eighteen million, two hundred eighteen thousand, two hundred thirty-eight".