231312640 has 72 divisors (see below), whose sum is σ = 596729448. Its totient is φ = 85401600.

The previous prime is 231312619. The next prime is 231312643. The reversal of 231312640 is 46213132.

231312640 is digitally balanced in base 3, 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 4 ways, for example, as 19784704 + 211527936 = 4448^2 + 14544^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231312643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9690 + ... + 23590.

It is an arithmetic number, because the mean of its divisors is an integer number (8287909).

Almost surely, 2^231312640 is an apocalyptic number.

231312640 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 231312640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (298364724).

231312640 is an abundant number, since it is smaller than the sum of its proper divisors (365416808).

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

231312640 is a wasteful number, since it uses less digits than its factorization.

231312640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13935 (or 13921 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 231312640 is about 15208.9657768042. The cubic root of 231312640 is about 613.8559293023.

Adding to 231312640 its reverse (46213132), we get a palindrome (277525772).

The spelling of 231312640 in words is "two hundred thirty-one million, three hundred twelve thousand, six hundred forty".