646708208256 has 144 divisors (see below), whose sum is σ = 2045529707130. Its totient is φ = 195972142080.

The previous prime is 646708208243. The next prime is 646708208297. The reversal of 646708208256 is 652802807646.

It can be written as a sum of positive squares in only one way, i.e., 446469857856 + 200238350400 = 668184^2 + 447480^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2180355 + ... + 2459138.

Almost surely, 2^646708208256 is an apocalyptic number.

646708208256 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

646708208256 is an abundant number, since it is smaller than the sum of its proper divisors (1398821498874).

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

646708208256 is a wasteful number, since it uses less digits than its factorization.

646708208256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4639535 (or 4639509 counting only the distinct ones).

The product of its (nonzero) digits is 7741440, while the sum is 54.

The spelling of 646708208256 in words is "six hundred forty-six billion, seven hundred eight million, two hundred eight thousand, two hundred fifty-six".