20718128427856 has 10 divisors (see below), whose sum is σ = 40141373829002. Its totient is φ = 10359064213920.

The previous prime is 20718128427839. The next prime is 20718128427863. The reversal of 20718128427856 is 65872482181702.

It can be written as a sum of positive squares in only one way, i.e., 12763585083456 + 7954543344400 = 3572616^2 + 2820380^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20718128427794 and 20718128427803.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 647441513355 + ... + 647441513386.

Almost surely, 2^{20718128427856} is an apocalyptic number.

It is an amenable number.

20718128427856 is a deficient number, since it is larger than the sum of its proper divisors (19423245401146).

20718128427856 is a wasteful number, since it uses less digits than its factorization.

20718128427856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1294883026749 (or 1294883026743 counting only the distinct ones).

The product of its (nonzero) digits is 24084480, while the sum is 61.

The spelling of 20718128427856 in words is "twenty trillion, seven hundred eighteen billion, one hundred twenty-eight million, four hundred twenty-seven thousand, eight hundred fifty-six".