18399393 has 10 divisors (see below), whose sum is σ = 27485634. Its totient is φ = 12266208.

The previous prime is 18399377. The next prime is 18399413. The reversal of 18399393 is 39399381.

It can be written as a sum of positive squares in only one way, i.e., 13417569 + 4981824 = 3663^2 + 2232^2 .

It is not a de Polignac number, because 18399393 - 2⁴ = 18399377 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18395393) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 113496 + ... + 113657.

Almost surely, 2^18399393 is an apocalyptic number.

It is an amenable number.

18399393 is a deficient number, since it is larger than the sum of its proper divisors (9086241).

18399393 is an equidigital number, since it uses as much as digits as its factorization.

18399393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227165 (or 227156 counting only the distinct ones).

The product of its digits is 157464, while the sum is 45.

The square root of 18399393 is about 4289.4513635196. The cubic root of 18399393 is about 263.9983212703.

The spelling of 18399393 in words is "eighteen million, three hundred ninety-nine thousand, three hundred ninety-three".