21224533 has 4 divisors (see below), whose sum is σ = 23154048. Its totient is φ = 19295020.

The previous prime is 21224521. The next prime is 21224557. The reversal of 21224533 is 33542212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21224533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224503) 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 3 ways as a sum of consecutive naturals, for example, 964741 + ... + 964762.

It is an arithmetic number, because the mean of its divisors is an integer number (5788512).

Almost surely, 2^21224533 is an apocalyptic number.

It is an amenable number.

21224533 is a deficient number, since it is larger than the sum of its proper divisors (1929515).

21224533 is a wasteful number, since it uses less digits than its factorization.

21224533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1929514.

The product of its digits is 1440, while the sum is 22.

The square root of 21224533 is about 4607.0091165527. The cubic root of 21224533 is about 276.8722188199.

Adding to 21224533 its reverse (33542212), we get a palindrome (54766745).

The spelling of 21224533 in words is "twenty-one million, two hundred twenty-four thousand, five hundred thirty-three".