91617581 has 4 divisors (see below), whose sum is σ = 99946464. Its totient is φ = 83288700.

The previous prime is 91617569. The next prime is 91617611. The reversal of 91617581 is 18571619.

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: 18571619 = 11 ⋅1688329.

It is not a de Polignac number, because 91617581 - 2¹⁴ = 91601197 is a prime.

It is a super-2 number, since 2×91617581² = 16787562296583122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91617481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4164425 + ... + 4164446.

It is an arithmetic number, because the mean of its divisors is an integer number (24986616).

Almost surely, 2^91617581 is an apocalyptic number.

It is an amenable number.

91617581 is a deficient number, since it is larger than the sum of its proper divisors (8328883).

91617581 is a wasteful number, since it uses less digits than its factorization.

91617581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8328882.

The product of its digits is 15120, while the sum is 38.

The square root of 91617581 is about 9571.7073189688. The cubic root of 91617581 is about 450.8093762935.

The spelling of 91617581 in words is "ninety-one million, six hundred seventeen thousand, five hundred eighty-one".