640334836 has 12 divisors (see below), whose sum is σ = 1120779940. Its totient is φ = 320112000.

The previous prime is 640334813. The next prime is 640334867. The reversal of 640334836 is 638433046.

It can be written as a sum of positive squares in 2 ways, for example, as 171872100 + 468462736 = 13110^2 + 21644^2 .

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 640334795 and 640334804.

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, 23086 + ... + 42586.

Almost surely, 2^640334836 is an apocalyptic number.

It is an amenable number.

640334836 is a deficient number, since it is larger than the sum of its proper divisors (480445104).

640334836 is a wasteful number, since it uses less digits than its factorization.

640334836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27714 (or 27712 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 37.

The square root of 640334836 is about 25304.8381935155. The cubic root of 640334836 is about 861.9241377890.

The spelling of 640334836 in words is "six hundred forty million, three hundred thirty-four thousand, eight hundred thirty-six".