646785639 has 12 divisors (see below), whose sum is σ = 948190776. Its totient is φ = 424754352.

The previous prime is 646785589. The next prime is 646785679. The reversal of 646785639 is 936587646.

646785639 is a `hidden beast` number, since 6 + 4 + 6 + 78 + 563 + 9 = 666.

646785639 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 646785639 - 2⁷ = 646785511 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646785679) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 535704 + ... + 536909.

It is an arithmetic number, because the mean of its divisors is an integer number (79015898).

Almost surely, 2^646785639 is an apocalyptic number.

646785639 is a deficient number, since it is larger than the sum of its proper divisors (301405137).

646785639 is a wasteful number, since it uses less digits than its factorization.

646785639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1072686 (or 1072683 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 54.

The square root of 646785639 is about 25431.9806346262. The cubic root of 646785639 is about 864.8088450155.

The spelling of 646785639 in words is "six hundred forty-six million, seven hundred eighty-five thousand, six hundred thirty-nine".