640256308 has 24 divisors (see below), whose sum is σ = 1130734080. Its totient is φ = 317200800.

The previous prime is 640256303. The next prime is 640256311. The reversal of 640256308 is 803652046.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640256303) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 288210 + ... + 290422.

It is an arithmetic number, because the mean of its divisors is an integer number (47113920).

Almost surely, 2^640256308 is an apocalyptic number.

It is an amenable number.

640256308 is a deficient number, since it is larger than the sum of its proper divisors (490477772).

640256308 is a wasteful number, since it uses less digits than its factorization.

640256308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2847 (or 2845 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 34.

The square root of 640256308 is about 25303.2865059067. The cubic root of 640256308 is about 861.8889020852. Note that the first 3 decimals are identical.

The spelling of 640256308 in words is "six hundred forty million, two hundred fifty-six thousand, three hundred eight".