291231 has 6 divisors (see below), whose sum is σ = 420680. Its totient is φ = 194148.

The previous prime is 291217. The next prime is 291253. The reversal of 291231 is 132192.

It is a happy number.

It is not a de Polignac number, because 291231 - 2⁵ = 291199 is a prime.

It is a super-2 number, since 2×291231² = 169630990722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 291231.

It is not an unprimeable number, because it can be changed into a prime (291271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 16171 + ... + 16188.

2²⁹¹²³¹ is an apocalyptic number.

291231 is a deficient number, since it is larger than the sum of its proper divisors (129449).

291231 is a wasteful number, since it uses less digits than its factorization.

291231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32365 (or 32362 counting only the distinct ones).

The product of its digits is 108, while the sum is 18.

The square root of 291231 is about 539.6582251759. The cubic root of 291231 is about 66.2845838183.

The spelling of 291231 in words is "two hundred ninety-one thousand, two hundred thirty-one".