91115661 has 16 divisors (see below), whose sum is σ = 149523584. Its totient is φ = 48060864.

The previous prime is 91115623. The next prime is 91115669. The reversal of 91115661 is 16651119.

It is not a de Polignac number, because 91115661 - 2⁹ = 91115149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91115669) 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 15 ways as a sum of consecutive naturals, for example, 166606 + ... + 167151.

It is an arithmetic number, because the mean of its divisors is an integer number (9345224).

Almost surely, 2^91115661 is an apocalyptic number.

91115661 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

91115661 is a deficient number, since it is larger than the sum of its proper divisors (58407923).

91115661 is a wasteful number, since it uses less digits than its factorization.

91115661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333780.

The product of its digits is 1620, while the sum is 30.

The square root of 91115661 is about 9545.4523727270. The cubic root of 91115661 is about 449.9846266353.

The spelling of 91115661 in words is "ninety-one million, one hundred fifteen thousand, six hundred sixty-one".