91378665 has 32 divisors (see below), whose sum is σ = 185660160. Its totient is φ = 41772672.

The previous prime is 91378643. The next prime is 91378667. The reversal of 91378665 is 56687319.

It is a happy number.

It is not a de Polignac number, because 91378665 - 2⁸ = 91378409 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 91378665.

It is not an unprimeable number, because it can be changed into a prime (91378667) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 47404 + ... + 49293.

It is an arithmetic number, because the mean of its divisors is an integer number (5801880).

Almost surely, 2^91378665 is an apocalyptic number.

It is an amenable number.

91378665 is an abundant number, since it is smaller than the sum of its proper divisors (94281495).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91378665 is a wasteful number, since it uses less digits than its factorization.

91378665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96718 (or 96712 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 91378665 is about 9559.2188488391. The cubic root of 91378665 is about 450.4171687033.

The spelling of 91378665 in words is "ninety-one million, three hundred seventy-eight thousand, six hundred sixty-five".