91579561 has 4 divisors (see below), whose sum is σ = 96966612. Its totient is φ = 86192512.

The previous prime is 91579559. The next prime is 91579591. The reversal of 91579561 is 16597519.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 64080025 + 27499536 = 8005^2 + 5244^2 .

It is a cyclic number.

It is not a de Polignac number, because 91579561 - 2¹ = 91579559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91579541) 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, 2693500 + ... + 2693533.

It is an arithmetic number, because the mean of its divisors is an integer number (24241653).

Almost surely, 2^91579561 is an apocalyptic number.

It is an amenable number.

91579561 is a deficient number, since it is larger than the sum of its proper divisors (5387051).

91579561 is a wasteful number, since it uses less digits than its factorization.

91579561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5387050.

The product of its digits is 85050, while the sum is 43.

The square root of 91579561 is about 9569.7210513160. The cubic root of 91579561 is about 450.7470078275.

The spelling of 91579561 in words is "ninety-one million, five hundred seventy-nine thousand, five hundred sixty-one".