21108224 has 20 divisors (see below), whose sum is σ = 42176244. Its totient is φ = 10553856.

The previous prime is 21108209. The next prime is 21108233. The reversal of 21108224 is 42280112.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21108196 and 21108205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20102 + ... + 21125.

Almost surely, 2^21108224 is an apocalyptic number.

It is an amenable number.

21108224 is a deficient number, since it is larger than the sum of its proper divisors (21068020).

21108224 is an frugal number, since it uses more digits than its factorization.

21108224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41245 (or 41229 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 21108224 is about 4594.3687270397. The cubic root of 21108224 is about 276.3655451895.

Adding to 21108224 its reverse (42280112), we get a palindrome (63388336).

The spelling of 21108224 in words is "twenty-one million, one hundred eight thousand, two hundred twenty-four".