640953960 has 128 divisors (see below), whose sum is σ = 1986336000. Its totient is φ = 165335040.

The previous prime is 640953953. The next prime is 640953977. The reversal of 640953960 is 69359046.

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 31 ways as a sum of consecutive naturals, for example, 1069741 + ... + 1070339.

It is an arithmetic number, because the mean of its divisors is an integer number (15518250).

Almost surely, 2^640953960 is an apocalyptic number.

640953960 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 640953960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (993168000).

640953960 is an abundant number, since it is smaller than the sum of its proper divisors (1345382040).

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

640953960 is a wasteful number, since it uses less digits than its factorization.

640953960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 891 (or 887 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 42.

The square root of 640953960 is about 25317.0685506834. The cubic root of 640953960 is about 862.2018393888.

The spelling of 640953960 in words is "six hundred forty million, nine hundred fifty-three thousand, nine hundred sixty".