21223563 has 16 divisors (see below), whose sum is σ = 29613600. Its totient is φ = 13502720.

The previous prime is 21223519. The next prime is 21223583. The reversal of 21223563 is 36532212.

It is a cyclic number.

It is not a de Polignac number, because 21223563 - 2⁹ = 21223051 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21223583) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6373 + ... + 9113.

It is an arithmetic number, because the mean of its divisors is an integer number (1850850).

Almost surely, 2^21223563 is an apocalyptic number.

21223563 is a deficient number, since it is larger than the sum of its proper divisors (8390037).

21223563 is a wasteful number, since it uses less digits than its factorization.

21223563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2862.

The product of its digits is 2160, while the sum is 24.

The square root of 21223563 is about 4606.9038409761. The cubic root of 21223563 is about 276.8680008999.

Adding to 21223563 its reverse (36532212), we get a palindrome (57755775).

The spelling of 21223563 in words is "twenty-one million, two hundred twenty-three thousand, five hundred sixty-three".