640493568 has 384 divisors, whose sum is σ = 2256508800. Its totient is φ = 179159040.

The previous prime is 640493563. The next prime is 640493603. The reversal of 640493568 is 865394046.

640493568 is a `hidden beast` number, since 6 + 40 + 49 + 3 + 568 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is not an unprimeable number, because it can be changed into a prime (640493563) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 49268730 + ... + 49268742.

It is an arithmetic number, because the mean of its divisors is an integer number (5876325).

Almost surely, 2^640493568 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 640493568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1128254400).

640493568 is an abundant number, since it is smaller than the sum of its proper divisors (1616015232).

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

640493568 is an equidigital number, since it uses as much as digits as its factorization.

640493568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67 (or 29 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The square root of 640493568 is about 25307.9743954351. The cubic root of 640493568 is about 861.9953524260.

The spelling of 640493568 in words is "six hundred forty million, four hundred ninety-three thousand, five hundred sixty-eight".