91140561 has 6 divisors (see below), whose sum is σ = 131647490. Its totient is φ = 60760368.

The previous prime is 91140547. The next prime is 91140563. The reversal of 91140561 is 16504119.

91140561 is a `hidden beast` number, since 91 + 14 + 0 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 74494161 + 16646400 = 8631^2 + 4080^2 .

It is not a de Polignac number, because 91140561 - 2²⁶ = 24031697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91140563) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5063356 + ... + 5063373.

Almost surely, 2^91140561 is an apocalyptic number.

It is an amenable number.

91140561 is a deficient number, since it is larger than the sum of its proper divisors (40506929).

91140561 is a wasteful number, since it uses less digits than its factorization.

91140561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10126735 (or 10126732 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 91140561 is about 9546.7565696419. The cubic root of 91140561 is about 450.0256133569.

The spelling of 91140561 in words is "ninety-one million, one hundred forty thousand, five hundred sixty-one".