91559561 has 4 divisors (see below), whose sum is σ = 92503572. Its totient is φ = 90615552.

The previous prime is 91559549. The next prime is 91559609. The reversal of 91559561 is 16595519.

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 70224400 + 21335161 = 8380^2 + 4619^2 .

It is a cyclic number.

It is not a de Polignac number, because 91559561 - 2¹⁸ = 91297417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91555561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 471860 + ... + 472053.

It is an arithmetic number, because the mean of its divisors is an integer number (23125893).

Almost surely, 2^91559561 is an apocalyptic number.

It is an amenable number.

91559561 is a deficient number, since it is larger than the sum of its proper divisors (944011).

91559561 is an equidigital number, since it uses as much as digits as its factorization.

91559561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 944010.

The product of its digits is 60750, while the sum is 41.

The square root of 91559561 is about 9568.6760317193. The cubic root of 91559561 is about 450.7141926579.

The spelling of 91559561 in words is "ninety-one million, five hundred fifty-nine thousand, five hundred sixty-one".