21344224 has 24 divisors (see below), whose sum is σ = 45842328. Its totient is φ = 9701760.

The previous prime is 21344209. The next prime is 21344237. The reversal of 21344224 is 42244312.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 21344195 and 21344204.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 29967 + ... + 30670.

It is an arithmetic number, because the mean of its divisors is an integer number (1910097).

Almost surely, 2^21344224 is an apocalyptic number.

It is an amenable number.

21344224 is an abundant number, since it is smaller than the sum of its proper divisors (24498104).

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

21344224 is a wasteful number, since it uses less digits than its factorization.

21344224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60658 (or 60650 counting only the distinct ones).

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

The square root of 21344224 is about 4619.9809523417. The cubic root of 21344224 is about 277.3916965023.

Adding to 21344224 its reverse (42244312), we get a palindrome (63588536).

The spelling of 21344224 in words is "twenty-one million, three hundred forty-four thousand, two hundred twenty-four".