231530640 has 80 divisors (see below), whose sum is σ = 783003456. Its totient is φ = 56128000.

The previous prime is 231530617. The next prime is 231530657. The reversal of 231530640 is 46035132.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 231530640.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41211 + ... + 46490.

Almost surely, 2^231530640 is an apocalyptic number.

231530640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

231530640 is an abundant number, since it is smaller than the sum of its proper divisors (551472816).

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

231530640 is a wasteful number, since it uses less digits than its factorization.

231530640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87728 (or 87722 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 231530640 is about 15216.1309142633. The cubic root of 231530640 is about 614.0487110643.

Adding to 231530640 its reverse (46035132), we get a palindrome (277565772).

The spelling of 231530640 in words is "two hundred thirty-one million, five hundred thirty thousand, six hundred forty".