18387331 has 2 divisors, whose sum is σ = 18387332. Its totient is φ = 18387330.

The previous prime is 18387323. The next prime is 18387349. The reversal of 18387331 is 13378381.

It is a weak prime.

It is an emirp because it is prime and its reverse (13378381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18387331 - 2³ = 18387323 is a prime.

It is a super-2 number, since 2×18387331² = 676187882607122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18387301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9193665 + 9193666.

It is an arithmetic number, because the mean of its divisors is an integer number (9193666).

Almost surely, 2^18387331 is an apocalyptic number.

18387331 is a deficient number, since it is larger than the sum of its proper divisors (1).

18387331 is an equidigital number, since it uses as much as digits as its factorization.

18387331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 34.

The square root of 18387331 is about 4288.0451256954. The cubic root of 18387331 is about 263.9406192970.

The spelling of 18387331 in words is "eighteen million, three hundred eighty-seven thousand, three hundred thirty-one".