91565257 has 4 divisors (see below), whose sum is σ = 104646016. Its totient is φ = 78484500.

The previous prime is 91565251. The next prime is 91565261. The reversal of 91565257 is 75256519.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 75256519 = 13 ⋅5788963.

It is a cyclic number.

It is not a de Polignac number, because 91565257 - 2¹⁵ = 91532489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91565251) 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, 6540369 + ... + 6540382.

It is an arithmetic number, because the mean of its divisors is an integer number (26161504).

Almost surely, 2^91565257 is an apocalyptic number.

It is an amenable number.

91565257 is a deficient number, since it is larger than the sum of its proper divisors (13080759).

91565257 is a wasteful number, since it uses less digits than its factorization.

91565257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13080758.

The product of its digits is 94500, while the sum is 40.

The square root of 91565257 is about 9568.9736649235. The cubic root of 91565257 is about 450.7235389048.

The spelling of 91565257 in words is "ninety-one million, five hundred sixty-five thousand, two hundred fifty-seven".