20013721563636 has 18 divisors (see below), whose sum is σ = 50590240619282. Its totient is φ = 6671240521200.

The previous prime is 20013721563529. The next prime is 20013721563677. The reversal of 20013721563636 is 63636512731002.

It is a happy number.

20013721563636 is a `hidden beast` number, since 2 + 0 + 0 + 1 + 3 + 7 + 2 + 1 + 5 + 6 + 3 + 636 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19804547052900 + 209174510736 = 4450230^2 + 457356^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a junction number, because it is equal to n+sod(n) for n = 20013721563591 and 20013721563600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 277968355015 + ... + 277968355086.

Almost surely, 2^{20013721563636} is an apocalyptic number.

It is an amenable number.

20013721563636 is an abundant number, since it is smaller than the sum of its proper divisors (30576519055646).

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

20013721563636 is a wasteful number, since it uses less digits than its factorization.

20013721563636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555936710111 (or 555936710106 counting only the distinct ones).

The product of its (nonzero) digits is 816480, while the sum is 45.

The spelling of 20013721563636 in words is "twenty trillion, thirteen billion, seven hundred twenty-one million, five hundred sixty-three thousand, six hundred thirty-six".