231138 has 12 divisors (see below), whose sum is σ = 500838. Its totient is φ = 77040.

The previous prime is 231131. The next prime is 231169. The reversal of 231138 is 831132.

231138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 199809 + 31329 = 447^2 + 177^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 12841 = 231138 / (2 + 3 + 1 + 1 + 3 + 8).

It is a self number, because there is not a number n which added to its sum of digits gives 231138.

It is not an unprimeable number, because it can be changed into a prime (231131) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6403 + ... + 6438.

2²³¹¹³⁸ is an apocalyptic number.

231138 is an abundant number, since it is smaller than the sum of its proper divisors (269700).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

231138 is a wasteful number, since it uses less digits than its factorization.

231138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12849 (or 12846 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 231138 is about 480.7681353834. The cubic root of 231138 is about 61.3701404254.

It can be divided in two parts, 231 and 138, that multiplied together give a triangular number (31878 = T₂₅₂).

The spelling of 231138 in words is "two hundred thirty-one thousand, one hundred thirty-eight".