18391271 has 2 divisors, whose sum is σ = 18391272. Its totient is φ = 18391270.

The previous prime is 18391213. The next prime is 18391319. The reversal of 18391271 is 17219381.

It is a strong prime.

It is an emirp because it is prime and its reverse (17219381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18391271 - 2⁶ = 18391207 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18391171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9195635 + 9195636.

It is an arithmetic number, because the mean of its divisors is an integer number (9195636).

Almost surely, 2^18391271 is an apocalyptic number.

18391271 is a deficient number, since it is larger than the sum of its proper divisors (1).

18391271 is an equidigital number, since it uses as much as digits as its factorization.

18391271 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 32.

The square root of 18391271 is about 4288.5045178943. The cubic root of 18391271 is about 263.9594701708.

The spelling of 18391271 in words is "eighteen million, three hundred ninety-one thousand, two hundred seventy-one".