646785638 has 8 divisors (see below), whose sum is σ = 1027247832. Its totient is φ = 304369696.

The previous prime is 646785589. The next prime is 646785679. The reversal of 646785638 is 836587646.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 646785638.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9511520 + ... + 9511587.

It is an arithmetic number, because the mean of its divisors is an integer number (128405979).

Almost surely, 2^646785638 is an apocalyptic number.

646785638 is a deficient number, since it is larger than the sum of its proper divisors (380462194).

646785638 is a wasteful number, since it uses less digits than its factorization.

646785638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19023126.

The product of its digits is 5806080, while the sum is 53.

The square root of 646785638 is about 25431.9806149659. The cubic root of 646785638 is about 864.8088445698.

The spelling of 646785638 in words is "six hundred forty-six million, seven hundred eighty-five thousand, six hundred thirty-eight".