21120224 has 24 divisors (see below), whose sum is σ = 42550200. Its totient is φ = 10313856.

The previous prime is 21120223. The next prime is 21120251. The reversal of 21120224 is 42202112.

It is a junction number, because it is equal to n+sod(n) for n = 21120199 and 21120208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120223) 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, 6299 + ... + 9050.

It is an arithmetic number, because the mean of its divisors is an integer number (1772925).

Almost surely, 2^21120224 is an apocalyptic number.

It is an amenable number.

21120224 is an abundant number, since it is smaller than the sum of its proper divisors (21429976).

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

21120224 is a wasteful number, since it uses less digits than its factorization.

21120224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15402 (or 15394 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21120224 is about 4595.6744880376. The cubic root of 21120224 is about 276.4179064286.

Adding to 21120224 its reverse (42202112), we get a palindrome (63322336).

The spelling of 21120224 in words is "twenty-one million, one hundred twenty thousand, two hundred twenty-four".