16563362561 has 4 divisors (see below), whose sum is σ = 16564786224. Its totient is φ = 16561938900.

The previous prime is 16563362551. The next prime is 16563362579. The reversal of 16563362561 is 16526336561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16563362561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16563362551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 694235 + ... + 717696.

It is an arithmetic number, because the mean of its divisors is an integer number (4141196556).

Almost surely, 2^16563362561 is an apocalyptic number.

It is an amenable number.

16563362561 is a deficient number, since it is larger than the sum of its proper divisors (1423663).

16563362561 is a wasteful number, since it uses less digits than its factorization.

16563362561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1423662.

The product of its digits is 583200, while the sum is 44.

The spelling of 16563362561 in words is "sixteen billion, five hundred sixty-three million, three hundred sixty-two thousand, five hundred sixty-one".