640318844 has 12 divisors (see below), whose sum is σ = 1222426968. Its totient is φ = 291054000.

The previous prime is 640318831. The next prime is 640318859. The reversal of 640318844 is 448813046.

It is a junction number, because it is equal to n+sod(n) for n = 640318798 and 640318807.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7276307 + ... + 7276394.

It is an arithmetic number, because the mean of its divisors is an integer number (101868914).

Almost surely, 2^640318844 is an apocalyptic number.

It is an amenable number.

640318844 is a deficient number, since it is larger than the sum of its proper divisors (582108124).

640318844 is a wasteful number, since it uses less digits than its factorization.

640318844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14552716 (or 14552714 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 38.

The square root of 640318844 is about 25304.5222045389. The cubic root of 640318844 is about 861.9169623735.

The spelling of 640318844 in words is "six hundred forty million, three hundred eighteen thousand, eight hundred forty-four".