12809705856 has 32 divisors (see below), whose sum is σ = 34025782200. Its totient is φ = 4269901824.

The previous prime is 12809705807. The next prime is 12809705863. The reversal of 12809705856 is 65850790821.

It is a tau number, because it is divible by the number of its divisors (32).

It is a junction number, because it is equal to n+sod(n) for n = 12809705799 and 12809705808.

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, 16678921 + ... + 16679688.

Almost surely, 2^12809705856 is an apocalyptic number.

12809705856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

12809705856 is an abundant number, since it is smaller than the sum of its proper divisors (21216076344).

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

12809705856 is an equidigital number, since it uses as much as digits as its factorization.

12809705856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33358626 (or 33358614 counting only the distinct ones).

The product of its (nonzero) digits is 1209600, while the sum is 51.

The spelling of 12809705856 in words is "twelve billion, eight hundred nine million, seven hundred five thousand, eight hundred fifty-six".