231331520 has 112 divisors (see below), whose sum is σ = 640250688. Its totient is φ = 77967360.

The previous prime is 231331519. The next prime is 231331523. The reversal of 231331520 is 25133132.

231331520 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 231331492 and 231331501.

It is not an unprimeable number, because it can be changed into a prime (231331523) 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, 135794 + ... + 137486.

It is an arithmetic number, because the mean of its divisors is an integer number (5716524).

Almost surely, 2^231331520 is an apocalyptic number.

231331520 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 231331520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (320125344).

231331520 is an abundant number, since it is smaller than the sum of its proper divisors (408919168).

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

231331520 is a wasteful number, since it uses less digits than its factorization.

231331520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1778 (or 1768 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 20.

The square root of 231331520 is about 15209.5864506567. The cubic root of 231331520 is about 613.8726300536.

Adding to 231331520 its reverse (25133132), we get a palindrome (256464652).

It can be divided in two parts, 2313 and 31520, that added together give a palindrome (33833).

The spelling of 231331520 in words is "two hundred thirty-one million, three hundred thirty-one thousand, five hundred twenty".