640750220 has 24 divisors (see below), whose sum is σ = 1467901008. Its totient is φ = 233000000.

The previous prime is 640750219. The next prime is 640750237. The reversal of 640750220 is 22057046.

It is a self number, because there is not a number n which added to its sum of digits gives 640750220.

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 7 ways as a sum of consecutive naturals, for example, 1456031 + ... + 1456470.

It is an arithmetic number, because the mean of its divisors is an integer number (61162542).

Almost surely, 2^640750220 is an apocalyptic number.

It is an amenable number.

640750220 is an abundant number, since it is smaller than the sum of its proper divisors (827150788).

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

640750220 is a wasteful number, since it uses less digits than its factorization.

640750220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2912521 (or 2912519 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 640750220 is about 25313.0444632802. The cubic root of 640750220 is about 862.1104736902.

The spelling of 640750220 in words is "six hundred forty million, seven hundred fifty thousand, two hundred twenty".