18912331 has 2 divisors, whose sum is σ = 18912332. Its totient is φ = 18912330.

The previous prime is 18912317. The next prime is 18912337. The reversal of 18912331 is 13321981.

It is a strong prime.

It is an emirp because it is prime and its reverse (13321981) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18912331 is a prime.

It is a super-2 number, since 2×18912331² = 715352527707122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18912331.

It is not a weakly prime, because it can be changed into another prime (18912337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9456165 + 9456166.

It is an arithmetic number, because the mean of its divisors is an integer number (9456166).

Almost surely, 2^18912331 is an apocalyptic number.

18912331 is a deficient number, since it is larger than the sum of its proper divisors (1).

18912331 is an equidigital number, since it uses as much as digits as its factorization.

18912331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 28.

The square root of 18912331 is about 4348.8309923473. The cubic root of 18912331 is about 266.4291177926.

The spelling of 18912331 in words is "eighteen million, nine hundred twelve thousand, three hundred thirty-one".