21222444 has 12 divisors (see below), whose sum is σ = 49519064. Its totient is φ = 7074144.

The previous prime is 21222433. The next prime is 21222469. The reversal of 21222444 is 44422212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21222444.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 884257 + ... + 884280.

Almost surely, 2^21222444 is an apocalyptic number.

It is an amenable number.

21222444 is an abundant number, since it is smaller than the sum of its proper divisors (28296620).

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

21222444 is a wasteful number, since it uses less digits than its factorization.

21222444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1768544 (or 1768542 counting only the distinct ones).

The product of its digits is 1024, while the sum is 21.

The square root of 21222444 is about 4606.7823912141. The cubic root of 21222444 is about 276.8631349130.

Adding to 21222444 its reverse (44422212), we get a palindrome (65644656).

The spelling of 21222444 in words is "twenty-one million, two hundred twenty-two thousand, four hundred forty-four".