21373660660563 has 12 divisors (see below), whose sum is σ = 30873435943480. Its totient is φ = 14248936086336.

The previous prime is 21373660660549. The next prime is 21373660660591. The reversal of 21373660660563 is 36506606637312.

21373660660563 is a `hidden beast` number, since 2 + 1 + 3 + 73 + 6 + 6 + 0 + 6 + 6 + 0 + 563 = 666.

It is not a de Polignac number, because 21373660660563 - 2¹³ = 21373660652371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21373660660063) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13457878 + ... + 14962011.

Almost surely, 2^{21373660660563} is an apocalyptic number.

21373660660563 is a deficient number, since it is larger than the sum of its proper divisors (9499775282917).

21373660660563 is a wasteful number, since it uses less digits than its factorization.

21373660660563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28503458 (or 28503455 counting only the distinct ones).

The product of its (nonzero) digits is 14696640, while the sum is 54.

The spelling of 21373660660563 in words is "twenty-one trillion, three hundred seventy-three billion, six hundred sixty million, six hundred sixty thousand, five hundred sixty-three".