21224553 has 16 divisors (see below), whose sum is σ = 33386496. Its totient is φ = 11736720.

The previous prime is 21224521. The next prime is 21224557. The reversal of 21224553 is 35542212.

It is not a de Polignac number, because 21224553 - 2⁵ = 21224521 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21224557) 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 15 ways as a sum of consecutive naturals, for example, 15651 + ... + 16952.

It is an arithmetic number, because the mean of its divisors is an integer number (2086656).

Almost surely, 2^21224553 is an apocalyptic number.

It is an amenable number.

21224553 is a deficient number, since it is larger than the sum of its proper divisors (12161943).

21224553 is a wasteful number, since it uses less digits than its factorization.

21224553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32644.

The product of its digits is 2400, while the sum is 24.

The square root of 21224553 is about 4607.0112871579. The cubic root of 21224553 is about 276.8723057860.

Adding to 21224553 its reverse (35542212), we get a palindrome (56766765).

The spelling of 21224553 in words is "twenty-one million, two hundred twenty-four thousand, five hundred fifty-three".