18213818 has 16 divisors (see below), whose sum is σ = 32867520. Its totient is φ = 7394976.

The previous prime is 18213803. The next prime is 18213823. The reversal of 18213818 is 81831281.

It is a happy number.

It is a super-2 number, since 2×18213818² = 663486332274248, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33971 + ... + 34502.

It is an arithmetic number, because the mean of its divisors is an integer number (2054220).

Almost surely, 2^18213818 is an apocalyptic number.

18213818 is a deficient number, since it is larger than the sum of its proper divisors (14653702).

18213818 is a wasteful number, since it uses less digits than its factorization.

18213818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68501.

The product of its digits is 3072, while the sum is 32.

The square root of 18213818 is about 4267.7649888437. The cubic root of 18213818 is about 263.1077642489.

The spelling of 18213818 in words is "eighteen million, two hundred thirteen thousand, eight hundred eighteen".