18391459 has 2 divisors, whose sum is σ = 18391460. Its totient is φ = 18391458.

The previous prime is 18391447. The next prime is 18391469. The reversal of 18391459 is 95419381.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18391459 - 2²¹ = 16294307 is a prime.

It is not a weakly prime, because it can be changed into another prime (18391409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9195729 + 9195730.

It is an arithmetic number, because the mean of its divisors is an integer number (9195730).

Almost surely, 2^18391459 is an apocalyptic number.

18391459 is a deficient number, since it is larger than the sum of its proper divisors (1).

18391459 is an equidigital number, since it uses as much as digits as its factorization.

18391459 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 40.

The square root of 18391459 is about 4288.5264369011. The cubic root of 18391459 is about 263.9603695868.

The spelling of 18391459 in words is "eighteen million, three hundred ninety-one thousand, four hundred fifty-nine".