21104563 has 2 divisors, whose sum is σ = 21104564. Its totient is φ = 21104562.

The previous prime is 21104561. The next prime is 21104569. The reversal of 21104563 is 36540112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21104563 - 2¹ = 21104561 is a prime.

Together with 21104561, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21104561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10552281 + 10552282.

It is an arithmetic number, because the mean of its divisors is an integer number (10552282).

Almost surely, 2^21104563 is an apocalyptic number.

21104563 is a deficient number, since it is larger than the sum of its proper divisors (1).

21104563 is an equidigital number, since it uses as much as digits as its factorization.

21104563 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 21104563 is about 4593.9702872352. The cubic root of 21104563 is about 276.3495666976.

Adding to 21104563 its reverse (36540112), we get a palindrome (57644675).

The spelling of 21104563 in words is "twenty-one million, one hundred four thousand, five hundred sixty-three".