231681 has 8 divisors (see below), whose sum is σ = 319680. Its totient is φ = 149072.

The previous prime is 231677. The next prime is 231701. The reversal of 231681 is 186132.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 231681 - 2² = 231677 is a prime.

It is a super-2 number, since 2×231681² = 107352171522, which contains 22 as substring.

It is an Ulam number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 231681.

It is not an unprimeable number, because it can be changed into a prime (231611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1245 + ... + 1418.

It is an arithmetic number, because the mean of its divisors is an integer number (39960).

2²³¹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

231681 is a deficient number, since it is larger than the sum of its proper divisors (87999).

231681 is a wasteful number, since it uses less digits than its factorization.

231681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2695.

The product of its digits is 288, while the sum is 21.

The square root of 231681 is about 481.3325253918. The cubic root of 231681 is about 61.4181606916.

The spelling of 231681 in words is "two hundred thirty-one thousand, six hundred eighty-one".