21118224 has 40 divisors (see below), whose sum is σ = 55487520. Its totient is φ = 6919168.

The previous prime is 21118219. The next prime is 21118247. The reversal of 21118224 is 42281112.

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 21118224.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 897 + ... + 6560.

It is an arithmetic number, because the mean of its divisors is an integer number (1387188).

Almost surely, 2^21118224 is an apocalyptic number.

21118224 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21118224 is an abundant number, since it is smaller than the sum of its proper divisors (34369296).

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

21118224 is a wasteful number, since it uses less digits than its factorization.

21118224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7527 (or 7521 counting only the distinct ones).

The product of its digits is 256, while the sum is 21.

The square root of 21118224 is about 4595.4568869700. The cubic root of 21118224 is about 276.4091809330.

Adding to 21118224 its reverse (42281112), we get a palindrome (63399336).

The spelling of 21118224 in words is "twenty-one million, one hundred eighteen thousand, two hundred twenty-four".