18231791 has 2 divisors, whose sum is σ = 18231792. Its totient is φ = 18231790.

The previous prime is 18231781. The next prime is 18231793. The reversal of 18231791 is 19713281.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18231791 - 2²² = 14037487 is a prime.

Together with 18231793, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18231793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9115895 + 9115896.

It is an arithmetic number, because the mean of its divisors is an integer number (9115896).

Almost surely, 2^18231791 is an apocalyptic number.

18231791 is a deficient number, since it is larger than the sum of its proper divisors (1).

18231791 is an equidigital number, since it uses as much as digits as its factorization.

18231791 is an evil number, because the sum of its binary digits is even.

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

The square root of 18231791 is about 4269.8701385405. The cubic root of 18231791 is about 263.1942788072.

The spelling of 18231791 in words is "eighteen million, two hundred thirty-one thousand, seven hundred ninety-one".