231840 has 144 divisors (see below), whose sum is σ = 943488. Its totient is φ = 50688.

The previous prime is 231839. The next prime is 231841. The reversal of 231840 is 48132.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (231839) and next prime (231841).

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10069 + ... + 10091.

It is an arithmetic number, because the mean of its divisors is an integer number (6552).

2²³¹⁸⁴⁰ is an apocalyptic number.

231840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (471744).

231840 is an abundant number, since it is smaller than the sum of its proper divisors (711648).

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

231840 is a wasteful number, since it uses less digits than its factorization.

231840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51 (or 40 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 231840 is about 481.4976635457. The cubic root of 231840 is about 61.4322076706.

231840 divided by its sum of digits (18) gives a triangular number (12880 = T₁₆₀).

Adding to 231840 its reverse (48132), we get a palindrome (279972).

The spelling of 231840 in words is "two hundred thirty-one thousand, eight hundred forty".