91087765 has 16 divisors (see below), whose sum is σ = 113135616. Its totient is φ = 70329600.

The previous prime is 91087757. The next prime is 91087771. The reversal of 91087765 is 56778019.

It is not a de Polignac number, because 91087765 - 2³ = 91087757 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 91420 + ... + 92410.

It is an arithmetic number, because the mean of its divisors is an integer number (7070976).

Almost surely, 2^91087765 is an apocalyptic number.

It is an amenable number.

91087765 is a deficient number, since it is larger than the sum of its proper divisors (22047851).

91087765 is a wasteful number, since it uses less digits than its factorization.

91087765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1620.

The product of its (nonzero) digits is 105840, while the sum is 43.

The square root of 91087765 is about 9543.9910414878. The cubic root of 91087765 is about 449.9386994687.

The spelling of 91087765 in words is "ninety-one million, eighty-seven thousand, seven hundred sixty-five".