640253646 has 40 divisors (see below), whose sum is σ = 1465184160. Its totient is φ = 208874592.

The previous prime is 640253639. The next prime is 640253657. The reversal of 640253646 is 646352046.

640253646 is a `hidden beast` number, since 6 + 4 + 0 + 2 + 5 + 3 + 646 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 640253646.

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 19 ways as a sum of consecutive naturals, for example, 34431 + ... + 49658.

It is an arithmetic number, because the mean of its divisors is an integer number (36629604).

Almost surely, 2^640253646 is an apocalyptic number.

640253646 is an abundant number, since it is smaller than the sum of its proper divisors (824930514).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640253646 is a wasteful number, since it uses less digits than its factorization.

640253646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84150 (or 84141 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 640253646 is about 25303.2339039894. The cubic root of 640253646 is about 861.8877075889.

The spelling of 640253646 in words is "six hundred forty million, two hundred fifty-three thousand, six hundred forty-six".