664765091 has 2 divisors, whose sum is σ = 664765092. Its totient is φ = 664765090.

The previous prime is 664765081. The next prime is 664765163. The reversal of 664765091 is 190567466.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664765091 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (664765081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332382545 + 332382546.

It is an arithmetic number, because the mean of its divisors is an integer number (332382546).

Almost surely, 2^664765091 is an apocalyptic number.

664765091 is a deficient number, since it is larger than the sum of its proper divisors (1).

664765091 is an equidigital number, since it uses as much as digits as its factorization.

664765091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 272160, while the sum is 44.

The square root of 664765091 is about 25783.0388240021. The cubic root of 664765091 is about 872.7490840906.

The spelling of 664765091 in words is "six hundred sixty-four million, seven hundred sixty-five thousand, ninety-one".