646785671 has 16 divisors (see below), whose sum is σ = 758419200. Its totient is φ = 540129408.

The previous prime is 646785589. The next prime is 646785679. The reversal of 646785671 is 176587646.

It is a de Polignac number, because none of the positive numbers 2^k-646785671 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 15 ways as a sum of consecutive naturals, for example, 39740 + ... + 53598.

It is an arithmetic number, because the mean of its divisors is an integer number (47401200).

Almost surely, 2^646785671 is an apocalyptic number.

646785671 is a deficient number, since it is larger than the sum of its proper divisors (111633529).

646785671 is a wasteful number, since it uses less digits than its factorization.

646785671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14038.

The product of its digits is 1693440, while the sum is 50.

The square root of 646785671 is about 25431.9812637553. The cubic root of 646785671 is about 864.8088592777.

The spelling of 646785671 in words is "six hundred forty-six million, seven hundred eighty-five thousand, six hundred seventy-one".