18331331 has 2 divisors, whose sum is σ = 18331332. Its totient is φ = 18331330.

The previous prime is 18331303. The next prime is 18331349. The reversal of 18331331 is 13313381.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18331331 is a prime.

It is a super-2 number, since 2×18331331² = 672075392463122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18331297 and 18331306.

It is not a weakly prime, because it can be changed into another prime (18331301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9165665 + 9165666.

It is an arithmetic number, because the mean of its divisors is an integer number (9165666).

Almost surely, 2^18331331 is an apocalyptic number.

18331331 is a deficient number, since it is larger than the sum of its proper divisors (1).

18331331 is an equidigital number, since it uses as much as digits as its factorization.

18331331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 23.

The square root of 18331331 is about 4281.5103643457. The cubic root of 18331331 is about 263.6723964766.

The spelling of 18331331 in words is "eighteen million, three hundred thirty-one thousand, three hundred thirty-one".