231091 has 4 divisors (see below), whose sum is σ = 264112. Its totient is φ = 198072.

The previous prime is 231079. The next prime is 231107. The reversal of 231091 is 190132.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 231091 - 2¹⁵ = 198323 is a prime.

It is a Duffinian number.

231091 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (231001) 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, 16500 + ... + 16513.

It is an arithmetic number, because the mean of its divisors is an integer number (66028).

2²³¹⁰⁹¹ is an apocalyptic number.

231091 is a deficient number, since it is larger than the sum of its proper divisors (33021).

231091 is an equidigital number, since it uses as much as digits as its factorization.

231091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33020.

The product of its (nonzero) digits is 54, while the sum is 16.

The square root of 231091 is about 480.7192527869. The cubic root of 231091 is about 61.3659804400.

It can be divided in two parts, 2310 and 91, that added together give a 4-th power (2401 = 7⁴).

The spelling of 231091 in words is "two hundred thirty-one thousand, ninety-one".