231609 has 16 divisors (see below), whose sum is σ = 362880. Its totient is φ = 128640.

The previous prime is 231607. The next prime is 231611. The reversal of 231609 is 906132.

231609 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (231607) and next prime (231611).

It is not a de Polignac number, because 231609 - 2¹ = 231607 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (231607) 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, 727 + ... + 995.

It is an arithmetic number, because the mean of its divisors is an integer number (22680).

2²³¹⁶⁰⁹ is an apocalyptic number.

It is an amenable number.

231609 is a deficient number, since it is larger than the sum of its proper divisors (131271).

231609 is a wasteful number, since it uses less digits than its factorization.

231609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320.

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 231609 is about 481.2577272107. The cubic root of 231609 is about 61.4117976814.

The spelling of 231609 in words is "two hundred thirty-one thousand, six hundred nine".