640566528 has 288 divisors, whose sum is σ = 2123928576. Its totient is φ = 167215104.

The previous prime is 640566503. The next prime is 640566539. The reversal of 640566528 is 825665046.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 640566528.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3929775 + ... + 3929937.

It is an arithmetic number, because the mean of its divisors is an integer number (7374752).

Almost surely, 2^640566528 is an apocalyptic number.

640566528 is a gapful number since it is divisible by the number (68) 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 640566528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1061964288).

640566528 is an abundant number, since it is smaller than the sum of its proper divisors (1483362048).

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

640566528 is a wasteful number, since it uses less digits than its factorization.

640566528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249 (or 235 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 42.

The square root of 640566528 is about 25309.4157972878. The cubic root of 640566528 is about 862.0280817649.

The spelling of 640566528 in words is "six hundred forty million, five hundred sixty-six thousand, five hundred twenty-eight".