21223244 has 48 divisors (see below), whose sum is σ = 44755200. Its totient is φ = 8613696.

The previous prime is 21223219. The next prime is 21223261. The reversal of 21223244 is 44232212.

21223244 = T₃₅₂ + T₃₅₃ + ... + T₅₅₄.

It is an unprimeable number.

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, 47687 + ... + 48129.

It is an arithmetic number, because the mean of its divisors is an integer number (932400).

Almost surely, 2^21223244 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21223244, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22377600).

21223244 is an abundant number, since it is smaller than the sum of its proper divisors (23531956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21223244 is a wasteful number, since it uses less digits than its factorization.

21223244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 542 (or 540 counting only the distinct ones).

The product of its digits is 768, while the sum is 20.

The square root of 21223244 is about 4606.8692188948. The cubic root of 21223244 is about 276.8666137415.

Adding to 21223244 its reverse (44232212), we get a palindrome (65455456).

The spelling of 21223244 in words is "twenty-one million, two hundred twenty-three thousand, two hundred forty-four".