18243978 has 32 divisors (see below), whose sum is σ = 37604736. Its totient is φ = 5898048.

The previous prime is 18243959. The next prime is 18243983. The reversal of 18243978 is 87934281.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32476 + ... + 33032.

It is an arithmetic number, because the mean of its divisors is an integer number (1175148).

Almost surely, 2^18243978 is an apocalyptic number.

18243978 is an abundant number, since it is smaller than the sum of its proper divisors (19360758).

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

18243978 is a wasteful number, since it uses less digits than its factorization.

18243978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718.

The product of its digits is 96768, while the sum is 42.

The square root of 18243978 is about 4271.2969927178. The cubic root of 18243978 is about 263.2529096214.

The spelling of 18243978 in words is "eighteen million, two hundred forty-three thousand, nine hundred seventy-eight".