684637705856 has 64 divisors (see below), whose sum is σ = 1468992525000. Its totient is φ = 315954708480.

The previous prime is 684637705813. The next prime is 684637705901. The reversal of 684637705856 is 658507736486.

It is a happy number.

684637705856 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 592838401600 + 91799304256 = 769960^2 + 302984^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 684637705792 and 684637705801.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27025676 + ... + 27050996.

Almost surely, 2^684637705856 is an apocalyptic number.

It is an amenable number.

684637705856 is an abundant number, since it is smaller than the sum of its proper divisors (784354819144).

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

684637705856 is a wasteful number, since it uses less digits than its factorization.

684637705856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41597 (or 41585 counting only the distinct ones).

The product of its (nonzero) digits is 203212800, while the sum is 65.

The spelling of 684637705856 in words is "six hundred eighty-four billion, six hundred thirty-seven million, seven hundred five thousand, eight hundred fifty-six".