18997331 has 2 divisors, whose sum is σ = 18997332. Its totient is φ = 18997330.

The previous prime is 18997273. The next prime is 18997337. The reversal of 18997331 is 13379981.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18997331 - 2¹⁴ = 18980947 is a prime.

It is a super-2 number, since 2×18997331² = 721797170247122, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18997337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9498665 + 9498666.

It is an arithmetic number, because the mean of its divisors is an integer number (9498666).

Almost surely, 2^18997331 is an apocalyptic number.

18997331 is a deficient number, since it is larger than the sum of its proper divisors (1).

18997331 is an equidigital number, since it uses as much as digits as its factorization.

18997331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40824, while the sum is 41.

The square root of 18997331 is about 4358.5927774914. The cubic root of 18997331 is about 266.8276696134.

The spelling of 18997331 in words is "eighteen million, nine hundred ninety-seven thousand, three hundred thirty-one".