18315691 has 2 divisors, whose sum is σ = 18315692. Its totient is φ = 18315690.

The previous prime is 18315673. The next prime is 18315697. The reversal of 18315691 is 19651381.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18315691 - 2⁹ = 18315179 is a prime.

It is a plaindrome in base 16.

It is not a weakly prime, because it can be changed into another prime (18315697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9157845 + 9157846.

It is an arithmetic number, because the mean of its divisors is an integer number (9157846).

Almost surely, 2^18315691 is an apocalyptic number.

18315691 is a deficient number, since it is larger than the sum of its proper divisors (1).

18315691 is an equidigital number, since it uses as much as digits as its factorization.

18315691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 34.

The square root of 18315691 is about 4279.6835163362. The cubic root of 18315691 is about 263.5973881091.

The spelling of 18315691 in words is "eighteen million, three hundred fifteen thousand, six hundred ninety-one".