231591 has 16 divisors (see below), whose sum is σ = 345600. Its totient is φ = 137088.

The previous prime is 231589. The next prime is 231599. The reversal of 231591 is 195132.

231591 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 231591 - 2¹ = 231589 is a prime.

It is an Ulam number.

231591 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231599) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 850 + ... + 1088.

It is an arithmetic number, because the mean of its divisors is an integer number (21600).

2²³¹⁵⁹¹ is an apocalyptic number.

231591 is a deficient number, since it is larger than the sum of its proper divisors (114009).

231591 is a wasteful number, since it uses less digits than its factorization.

231591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278.

The product of its digits is 270, while the sum is 21.

The square root of 231591 is about 481.2390258489. The cubic root of 231591 is about 61.4102067228.

The spelling of 231591 in words is "two hundred thirty-one thousand, five hundred ninety-one".