21113563 has 8 divisors (see below), whose sum is σ = 22406400. Its totient is φ = 19852008.

The previous prime is 21113549. The next prime is 21113581. The reversal of 21113563 is 36531112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21113563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21113593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6423 + ... + 9136.

It is an arithmetic number, because the mean of its divisors is an integer number (2800800).

Almost surely, 2^21113563 is an apocalyptic number.

21113563 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21113563 is a deficient number, since it is larger than the sum of its proper divisors (1292837).

21113563 is a wasteful number, since it uses less digits than its factorization.

21113563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15641.

The product of its digits is 540, while the sum is 22.

The square root of 21113563 is about 4594.9497276902. The cubic root of 21113563 is about 276.3888440273.

Adding to 21113563 its reverse (36531112), we get a palindrome (57644675).

The spelling of 21113563 in words is "twenty-one million, one hundred thirteen thousand, five hundred sixty-three".