640528560 has 320 divisors, whose sum is σ = 2557455360. Its totient is φ = 146126592.

The previous prime is 640528547. The next prime is 640528579. The reversal of 640528560 is 65825046.

640528560 is a `hidden beast` number, since 6 + 40 + 52 + 8 + 560 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1224459 + ... + 1224981.

It is an arithmetic number, because the mean of its divisors is an integer number (7992048).

Almost surely, 2^640528560 is an apocalyptic number.

640528560 is a gapful number since it is divisible by the number (60) 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 640528560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1278727680).

640528560 is an abundant number, since it is smaller than the sum of its proper divisors (1916926800).

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

640528560 is an equidigital number, since it uses as much as digits as its factorization.

640528560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 564 (or 540 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 640528560 is about 25308.6657095944. The cubic root of 640528560 is about 862.0110498994.

The spelling of 640528560 in words is "six hundred forty million, five hundred twenty-eight thousand, five hundred sixty".