231304640 has 112 divisors (see below), whose sum is σ = 649979904. Its totient is φ = 76723200.

The previous prime is 231304639. The next prime is 231304643. The reversal of 231304640 is 46403132.

It is a happy number.

231304640 is digitally balanced in base 2, because in such base 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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (231304643) 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, 67775 + ... + 71105.

It is an arithmetic number, because the mean of its divisors is an integer number (5803392).

Almost surely, 2^231304640 is an apocalyptic number.

231304640 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 231304640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (324989952).

231304640 is an abundant number, since it is smaller than the sum of its proper divisors (418675264).

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

231304640 is a wasteful number, since it uses less digits than its factorization.

231304640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3386 (or 3376 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 231304640 is about 15208.7027717685. The cubic root of 231304640 is about 613.8488524387.

Adding to 231304640 its reverse (46403132), we get a palindrome (277707772).

The spelling of 231304640 in words is "two hundred thirty-one million, three hundred four thousand, six hundred forty".