21222424 has 16 divisors (see below), whose sum is σ = 39843720. Its totient is φ = 10597440.

The previous prime is 21222401. The next prime is 21222433. The reversal of 21222424 is 42422212.

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

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, 8164 + ... + 10444.

Almost surely, 2^21222424 is an apocalyptic number.

It is an amenable number.

21222424 is a deficient number, since it is larger than the sum of its proper divisors (18621296).

21222424 is a wasteful number, since it uses less digits than its factorization.

21222424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3450 (or 3446 counting only the distinct ones).

The product of its digits is 512, while the sum is 19.

The square root of 21222424 is about 4606.7802205011. The cubic root of 21222424 is about 276.8630479412.

Adding to 21222424 its reverse (42422212), we get a palindrome (63644636).

The spelling of 21222424 in words is "twenty-one million, two hundred twenty-two thousand, four hundred twenty-four".