91664869 has 2 divisors, whose sum is σ = 91664870. Its totient is φ = 91664868.

The previous prime is 91664857. The next prime is 91664879. The reversal of 91664869 is 96846619.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 89302500 + 2362369 = 9450^2 + 1537^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91664869 is a prime.

It is a super-2 number, since 2×91664869² = 16804896417574322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91664849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45832434 + 45832435.

It is an arithmetic number, because the mean of its divisors is an integer number (45832435).

Almost surely, 2^91664869 is an apocalyptic number.

It is an amenable number.

91664869 is a deficient number, since it is larger than the sum of its proper divisors (1).

91664869 is an equidigital number, since it uses as much as digits as its factorization.

91664869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 49.

The square root of 91664869 is about 9574.1771970233. The cubic root of 91664869 is about 450.8869240265.

The spelling of 91664869 in words is "ninety-one million, six hundred sixty-four thousand, eight hundred sixty-nine".