231128520 has 64 divisors (see below), whose sum is σ = 792443520. Its totient is φ = 52829184.

The previous prime is 231128509. The next prime is 231128531. The reversal of 231128520 is 25821132.

It is an interprime number because it is at equal distance from previous prime (231128509) and next prime (231128531).

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

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, 136737 + ... + 138416.

It is an arithmetic number, because the mean of its divisors is an integer number (12381930).

Almost surely, 2^231128520 is an apocalyptic number.

231128520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

231128520 is an abundant number, since it is smaller than the sum of its proper divisors (561315000).

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

231128520 is a wasteful number, since it uses less digits than its factorization.

231128520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275174 (or 275170 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 231128520 is about 15202.9115632500. The cubic root of 231128520 is about 613.6930139294.

Adding to 231128520 its reverse (25821132), we get a palindrome (256949652).

The spelling of 231128520 in words is "two hundred thirty-one million, one hundred twenty-eight thousand, five hundred twenty".