640452660 has 96 divisors (see below), whose sum is σ = 1832544000. Its totient is φ = 167086080.

The previous prime is 640452649. The next prime is 640452719. The reversal of 640452660 is 66254046.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 634236 + ... + 635244.

It is an arithmetic number, because the mean of its divisors is an integer number (19089000).

Almost surely, 2^640452660 is an apocalyptic number.

640452660 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 640452660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (916272000).

640452660 is an abundant number, since it is smaller than the sum of its proper divisors (1192091340).

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

640452660 is a wasteful number, since it uses less digits than its factorization.

640452660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1241 (or 1239 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 640452660 is about 25307.1661787724. The cubic root of 640452660 is about 861.9770002997.

The spelling of 640452660 in words is "six hundred forty million, four hundred fifty-two thousand, six hundred sixty".