21163563 has 6 divisors (see below), whose sum is σ = 30569604. Its totient is φ = 14109036.

The previous prime is 21163561. The next prime is 21163579. The reversal of 21163563 is 36536112.

21163563 is a `hidden beast` number, since 21 + 1 + 635 + 6 + 3 = 666.

It is not a de Polignac number, because 21163563 - 2¹ = 21163561 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21163561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1175745 + ... + 1175762.

It is an arithmetic number, because the mean of its divisors is an integer number (5094934).

Almost surely, 2^21163563 is an apocalyptic number.

21163563 is a deficient number, since it is larger than the sum of its proper divisors (9406041).

21163563 is a wasteful number, since it uses less digits than its factorization.

21163563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2351513 (or 2351510 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 21163563 is about 4600.3872663070. The cubic root of 21163563 is about 276.6068484085.

Adding to 21163563 its reverse (36536112), we get a palindrome (57699675).

The spelling of 21163563 in words is "twenty-one million, one hundred sixty-three thousand, five hundred sixty-three".