21563536803 has 4 divisors (see below), whose sum is σ = 28751382408. Its totient is φ = 14375691200.

The previous prime is 21563536751. The next prime is 21563536807. The reversal of 21563536803 is 30863536512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21563536803 - 2⁶ = 21563536739 is a prime.

It is a super-2 number, since 2×21563536803² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21563536807) 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, 3593922798 + ... + 3593922803.

It is an arithmetic number, because the mean of its divisors is an integer number (7187845602).

Almost surely, 2^21563536803 is an apocalyptic number.

21563536803 is a deficient number, since it is larger than the sum of its proper divisors (7187845605).

21563536803 is an equidigital number, since it uses as much as digits as its factorization.

21563536803 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7187845604.

The product of its (nonzero) digits is 388800, while the sum is 42.

The spelling of 21563536803 in words is "twenty-one billion, five hundred sixty-three million, five hundred thirty-six thousand, eight hundred three".