91305561 has 32 divisors (see below), whose sum is σ = 130636800. Its totient is φ = 56602304.

The previous prime is 91305499. The next prime is 91305581. The reversal of 91305561 is 16550319.

It is a cyclic number.

It is not a de Polignac number, because 91305561 - 2¹³ = 91297369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91305581) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 612715 + ... + 612863.

It is an arithmetic number, because the mean of its divisors is an integer number (4082400).

Almost surely, 2^91305561 is an apocalyptic number.

It is an amenable number.

91305561 is a deficient number, since it is larger than the sum of its proper divisors (39331239).

91305561 is a wasteful number, since it uses less digits than its factorization.

91305561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365.

The product of its (nonzero) digits is 4050, while the sum is 30.

The square root of 91305561 is about 9555.3943403713. The cubic root of 91305561 is about 450.2970236587.

The spelling of 91305561 in words is "ninety-one million, three hundred five thousand, five hundred sixty-one".