646859690670 has 16 divisors (see below), whose sum is σ = 1552463257680. Its totient is φ = 172495917504.

The previous prime is 646859690647. The next prime is 646859690677. The reversal of 646859690670 is 76096958646.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646859690677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10780994815 + ... + 10780994874.

It is an arithmetic number, because the mean of its divisors is an integer number (97028953605).

Almost surely, 2^646859690670 is an apocalyptic number.

646859690670 is an abundant number, since it is smaller than the sum of its proper divisors (905603567010).

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

646859690670 is a wasteful number, since it uses less digits than its factorization.

646859690670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21561989699.

The product of its (nonzero) digits is 117573120, while the sum is 66.

The spelling of 646859690670 in words is "six hundred forty-six billion, eight hundred fifty-nine million, six hundred ninety thousand, six hundred seventy".