231640128 has 112 divisors (see below), whose sum is σ = 699576960. Its totient is φ = 75105792.

The previous prime is 231640121. The next prime is 231640163. The reversal of 231640128 is 821046132.

231640128 is a `hidden beast` number, since 2 + 3 + 1 + 640 + 12 + 8 = 666.

It is a super-3 number, since 3×231640128³ (a number of 26 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (231640121) 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, 62125 + ... + 65747.

Almost surely, 2^231640128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231640128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (349788480).

231640128 is an abundant number, since it is smaller than the sum of its proper divisors (467936832).

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

231640128 is a wasteful number, since it uses less digits than its factorization.

231640128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3681 (or 3665 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 231640128 is about 15219.7282498736. The cubic root of 231640128 is about 614.1454878459.

The spelling of 231640128 in words is "two hundred thirty-one million, six hundred forty thousand, one hundred twenty-eight".