640234528 has 48 divisors (see below), whose sum is σ = 1298963736. Its totient is φ = 310487040.

The previous prime is 640234523. The next prime is 640234531. The reversal of 640234528 is 825432046.

It can be written as a sum of positive squares in 4 ways, for example, as 585059344 + 55175184 = 24188^2 + 7428^2 .

It is a junction number, because it is equal to n+sod(n) for n = 640234493 and 640234502.

It is not an unprimeable number, because it can be changed into a prime (640234523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 140250 + ... + 144742.

Almost surely, 2^640234528 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 640234528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (649481868).

640234528 is an abundant number, since it is smaller than the sum of its proper divisors (658729208).

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

640234528 is a wasteful number, since it uses less digits than its factorization.

640234528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4637 (or 4629 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 34.

The square root of 640234528 is about 25302.8561233707. The cubic root of 640234528 is about 861.8791288361.

The spelling of 640234528 in words is "six hundred forty million, two hundred thirty-four thousand, five hundred twenty-eight".