91245561 has 16 divisors (see below), whose sum is σ = 133740288. Its totient is φ = 54875600.

The previous prime is 91245533. The next prime is 91245587. The reversal of 91245561 is 16554219.

It is a cyclic number.

It is not a de Polignac number, because 91245561 - 2⁵ = 91245529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (91245061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6231 + ... + 14876.

It is an arithmetic number, because the mean of its divisors is an integer number (8358768).

Almost surely, 2^91245561 is an apocalyptic number.

It is an amenable number.

91245561 is a deficient number, since it is larger than the sum of its proper divisors (42494727).

91245561 is a wasteful number, since it uses less digits than its factorization.

91245561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21252.

The product of its digits is 10800, while the sum is 33.

The square root of 91245561 is about 9552.2542365664. The cubic root of 91245561 is about 450.1983668650.

It can be divided in two parts, 91245 and 561, that added together give a triangular number (91806 = T₄₂₈).

The spelling of 91245561 in words is "ninety-one million, two hundred forty-five thousand, five hundred sixty-one".