664715791 has 2 divisors, whose sum is σ = 664715792. Its totient is φ = 664715790.

The previous prime is 664715773. The next prime is 664715797. The reversal of 664715791 is 197517466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664715791 - 2¹⁷ = 664584719 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664715797) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332357895 + 332357896.

It is an arithmetic number, because the mean of its divisors is an integer number (332357896).

Almost surely, 2^664715791 is an apocalyptic number.

664715791 is a deficient number, since it is larger than the sum of its proper divisors (1).

664715791 is an equidigital number, since it uses as much as digits as its factorization.

664715791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 317520, while the sum is 46.

The square root of 664715791 is about 25782.0827513993. The cubic root of 664715791 is about 872.7275087532.

The spelling of 664715791 in words is "six hundred sixty-four million, seven hundred fifteen thousand, seven hundred ninety-one".