21442224 has 20 divisors (see below), whose sum is σ = 55392536. Its totient is φ = 7147392.

The previous prime is 21442163. The next prime is 21442229. The reversal of 21442224 is 42224412.

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 21442224.

It is not an unprimeable number, because it can be changed into a prime (21442229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 223309 + ... + 223404.

Almost surely, 2^21442224 is an apocalyptic number.

21442224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21442224 is an abundant number, since it is smaller than the sum of its proper divisors (33950312).

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

21442224 is a wasteful number, since it uses less digits than its factorization.

21442224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 446724 (or 446718 counting only the distinct ones).

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

The square root of 21442224 is about 4630.5749103108. The cubic root of 21442224 is about 277.8155877184.

Adding to 21442224 its reverse (42224412), we get a palindrome (63666636).

The spelling of 21442224 in words is "twenty-one million, four hundred forty-two thousand, two hundred twenty-four".