640564228 has 12 divisors (see below), whose sum is σ = 1124978652. Its totient is φ = 319141760.

The previous prime is 640564219. The next prime is 640564231. The reversal of 640564228 is 822465046.

It can be written as a sum of positive squares in 2 ways, for example, as 363741184 + 276823044 = 19072^2 + 16638^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 283825 + ... + 286072.

It is an arithmetic number, because the mean of its divisors is an integer number (93748221).

Almost surely, 2^640564228 is an apocalyptic number.

It is an amenable number.

640564228 is a deficient number, since it is larger than the sum of its proper divisors (484414424).

640564228 is a wasteful number, since it uses less digits than its factorization.

640564228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570182 (or 570180 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 37.

The square root of 640564228 is about 25309.3703596119. The cubic root of 640564228 is about 862.0270500391.

The spelling of 640564228 in words is "six hundred forty million, five hundred sixty-four thousand, two hundred twenty-eight".