640387870 has 16 divisors (see below), whose sum is σ = 1174448160. Its totient is φ = 251321824.

The previous prime is 640387859. The next prime is 640387871. The reversal of 640387870 is 78783046.

640387870 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 not an unprimeable number, because it can be changed into a prime (640387871) 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, 603610 + ... + 604669.

It is an arithmetic number, because the mean of its divisors is an integer number (73403010).

Almost surely, 2^640387870 is an apocalyptic number.

640387870 is a deficient number, since it is larger than the sum of its proper divisors (534060290).

640387870 is a wasteful number, since it uses less digits than its factorization.

640387870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1208339.

The product of its (nonzero) digits is 225792, while the sum is 43.

The square root of 640387870 is about 25305.8860741923. The cubic root of 640387870 is about 861.9479326435.

The spelling of 640387870 in words is "six hundred forty million, three hundred eighty-seven thousand, eight hundred seventy".