91312231 has 4 divisors (see below), whose sum is σ = 95282352. Its totient is φ = 87342112.

The previous prime is 91312217. The next prime is 91312237. The reversal of 91312231 is 13221319.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13221319 = 83 ⋅159293.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91312231 is a prime.

It is a super-2 number, since 2×91312231² = 16675847060394722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91312237) 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 3 ways as a sum of consecutive naturals, for example, 1985026 + ... + 1985071.

It is an arithmetic number, because the mean of its divisors is an integer number (23820588).

Almost surely, 2^91312231 is an apocalyptic number.

91312231 is a deficient number, since it is larger than the sum of its proper divisors (3970121).

91312231 is a wasteful number, since it uses less digits than its factorization.

91312231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3970120.

The product of its digits is 324, while the sum is 22.

The square root of 91312231 is about 9555.7433515138. The cubic root of 91312231 is about 450.3079883359.

The spelling of 91312231 in words is "ninety-one million, three hundred twelve thousand, two hundred thirty-one".