18239931 has 8 divisors (see below), whose sum is σ = 27022160. Its totient is φ = 12159936.

The previous prime is 18239917. The next prime is 18239933. The reversal of 18239931 is 13993281.

It is not a de Polignac number, because 18239931 - 2¹⁰ = 18238907 is a prime.

It is a super-2 number, since 2×18239931² = 665390165769522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18239933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 337750 + ... + 337803.

It is an arithmetic number, because the mean of its divisors is an integer number (3377770).

Almost surely, 2^18239931 is an apocalyptic number.

18239931 is a deficient number, since it is larger than the sum of its proper divisors (8782229).

18239931 is an equidigital number, since it uses as much as digits as its factorization.

18239931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 675562 (or 675556 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 18239931 is about 4270.8232227523. The cubic root of 18239931 is about 263.2334426807.

The spelling of 18239931 in words is "eighteen million, two hundred thirty-nine thousand, nine hundred thirty-one".