640708220 has 24 divisors (see below), whose sum is σ = 1346814000. Its totient is φ = 256030592.

The previous prime is 640708219. The next prime is 640708259. The reversal of 640708220 is 22807046.

640708220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5711 + ... + 36249.

It is an arithmetic number, because the mean of its divisors is an integer number (56117250).

Almost surely, 2^640708220 is an apocalyptic number.

It is an amenable number.

640708220 is an abundant number, since it is smaller than the sum of its proper divisors (706105780).

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

640708220 is a wasteful number, since it uses less digits than its factorization.

640708220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31597 (or 31595 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 29.

The square root of 640708220 is about 25312.2148378999. The cubic root of 640708220 is about 862.0916366926.

The spelling of 640708220 in words is "six hundred forty million, seven hundred eight thousand, two hundred twenty".