91665688 has 16 divisors (see below), whose sum is σ = 172327680. Its totient is φ = 45711648.

The previous prime is 91665661. The next prime is 91665689. The reversal of 91665688 is 88656619.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91665689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11895 + ... + 18022.

It is an arithmetic number, because the mean of its divisors is an integer number (10770480).

Almost surely, 2^91665688 is an apocalyptic number.

It is an amenable number.

91665688 is a deficient number, since it is larger than the sum of its proper divisors (80661992).

91665688 is a wasteful number, since it uses less digits than its factorization.

91665688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30306 (or 30302 counting only the distinct ones).

The product of its digits is 622080, while the sum is 49.

The square root of 91665688 is about 9574.2199682272. The cubic root of 91665688 is about 450.8882668721. Note that the first 3 decimals are identical.

The spelling of 91665688 in words is "ninety-one million, six hundred sixty-five thousand, six hundred eighty-eight".