91664857 has 2 divisors, whose sum is σ = 91664858. Its totient is φ = 91664856.

The previous prime is 91664851. The next prime is 91664869. The reversal of 91664857 is 75846619.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 90174016 + 1490841 = 9496^2 + 1221^2 .

It is a cyclic number.

It is not a de Polignac number, because 91664857 - 2³ = 91664849 is a prime.

It is not a weakly prime, because it can be changed into another prime (91664851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45832428 + 45832429.

It is an arithmetic number, because the mean of its divisors is an integer number (45832429).

Almost surely, 2^91664857 is an apocalyptic number.

It is an amenable number.

91664857 is a deficient number, since it is larger than the sum of its proper divisors (1).

91664857 is an equidigital number, since it uses as much as digits as its factorization.

91664857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 46.

The square root of 91664857 is about 9574.1765703375. The cubic root of 91664857 is about 450.8869043511.

The spelling of 91664857 in words is "ninety-one million, six hundred sixty-four thousand, eight hundred fifty-seven".