21116224 has 14 divisors (see below), whose sum is σ = 41902634. Its totient is φ = 10558080.

The previous prime is 21116219. The next prime is 21116257. The reversal of 21116224 is 42261112.

It can be written as a sum of positive squares in only one way, i.e., 20793600 + 322624 = 4560^2 + 568^2 .

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, 164907 + ... + 165034.

Almost surely, 2^21116224 is an apocalyptic number.

It is an amenable number.

21116224 is a deficient number, since it is larger than the sum of its proper divisors (20786410).

21116224 is an equidigital number, since it uses as much as digits as its factorization.

21116224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329953 (or 329943 counting only the distinct ones).

The product of its digits is 192, while the sum is 19.

The square root of 21116224 is about 4595.2392755982. The cubic root of 21116224 is about 276.4004548865.

Adding to 21116224 its reverse (42261112), we get a palindrome (63377336).

The spelling of 21116224 in words is "twenty-one million, one hundred sixteen thousand, two hundred twenty-four".