20563613521 has 16 divisors (see below), whose sum is σ = 22733424000. Its totient is φ = 18445536000.

The previous prime is 20563613479. The next prime is 20563613537. The reversal of 20563613521 is 12531636502.

It is a cyclic number.

It is not a de Polignac number, because 20563613521 - 2¹¹ = 20563611473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20563613921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 205945 + ... + 289033.

It is an arithmetic number, because the mean of its divisors is an integer number (1420839000).

Almost surely, 2^20563613521 is an apocalyptic number.

It is an amenable number.

20563613521 is a deficient number, since it is larger than the sum of its proper divisors (2169810479).

20563613521 is a wasteful number, since it uses less digits than its factorization.

20563613521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83400.

The product of its (nonzero) digits is 32400, while the sum is 34.

The spelling of 20563613521 in words is "twenty billion, five hundred sixty-three million, six hundred thirteen thousand, five hundred twenty-one".