91561079 has 4 divisors (see below), whose sum is σ = 92720160. Its totient is φ = 90402000.

The previous prime is 91561027. The next prime is 91561109. The reversal of 91561079 is 97016519.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97016519 = 359 ⋅270241.

It is a cyclic number.

It is not a de Polignac number, because 91561079 - 2⁸ = 91560823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91561279) 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, 579422 + ... + 579579.

It is an arithmetic number, because the mean of its divisors is an integer number (23180040).

Almost surely, 2^91561079 is an apocalyptic number.

91561079 is a deficient number, since it is larger than the sum of its proper divisors (1159081).

91561079 is a wasteful number, since it uses less digits than its factorization.

91561079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1159080.

The product of its (nonzero) digits is 17010, while the sum is 38.

The square root of 91561079 is about 9568.7553527091. The cubic root of 91561079 is about 450.7166834968.

The spelling of 91561079 in words is "ninety-one million, five hundred sixty-one thousand, seventy-nine".