91231611 has 4 divisors (see below), whose sum is σ = 121642152. Its totient is φ = 60821072.

The previous prime is 91231579. The next prime is 91231627. The reversal of 91231611 is 11613219.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11613219 = 3 ⋅3871073.

It is a cyclic number.

It is not a de Polignac number, because 91231611 - 2⁵ = 91231579 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91231211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15205266 + ... + 15205271.

It is an arithmetic number, because the mean of its divisors is an integer number (30410538).

Almost surely, 2^91231611 is an apocalyptic number.

91231611 is a deficient number, since it is larger than the sum of its proper divisors (30410541).

91231611 is a wasteful number, since it uses less digits than its factorization.

91231611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30410540.

The product of its digits is 324, while the sum is 24.

The square root of 91231611 is about 9551.5240145225. The cubic root of 91231611 is about 450.1754229642.

It can be divided in two parts, 912 and 31611, that added together give a palindrome (32523).

The spelling of 91231611 in words is "ninety-one million, two hundred thirty-one thousand, six hundred eleven".