21223444 has 12 divisors (see below), whose sum is σ = 40517568. Its totient is φ = 9647000.

The previous prime is 21223427. The next prime is 21223453. The reversal of 21223444 is 44432212.

It is a happy number.

It is a super-2 number, since 2×21223444² = 900869150442272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 241132 + ... + 241219.

It is an arithmetic number, because the mean of its divisors is an integer number (3376464).

Almost surely, 2^21223444 is an apocalyptic number.

It is an amenable number.

21223444 is a deficient number, since it is larger than the sum of its proper divisors (19294124).

21223444 is a wasteful number, since it uses less digits than its factorization.

21223444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 482366 (or 482364 counting only the distinct ones).

The product of its digits is 1536, while the sum is 22.

The square root of 21223444 is about 4606.8909255592. The cubic root of 21223444 is about 276.8674834349.

Adding to 21223444 its reverse (44432212), we get a palindrome (65655656).

The spelling of 21223444 in words is "twenty-one million, two hundred twenty-three thousand, four hundred forty-four".