18331398 has 12 divisors (see below), whose sum is σ = 39718068. Its totient is φ = 6110460.

The previous prime is 18331381. The next prime is 18331429. The reversal of 18331398 is 89313381.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 509188 + ... + 509223.

It is an arithmetic number, because the mean of its divisors is an integer number (3309839).

Almost surely, 2^18331398 is an apocalyptic number.

18331398 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18331398 is an abundant number, since it is smaller than the sum of its proper divisors (21386670).

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

18331398 is a wasteful number, since it uses less digits than its factorization.

18331398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1018419 (or 1018416 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 18331398 is about 4281.5181886803. The cubic root of 18331398 is about 263.6727177122.

The spelling of 18331398 in words is "eighteen million, three hundred thirty-one thousand, three hundred ninety-eight".