21224120 has 16 divisors (see below), whose sum is σ = 47754360. Its totient is φ = 8489632.

The previous prime is 21224087. The next prime is 21224123. The reversal of 21224120 is 2142212.

It is a junction number, because it is equal to n+sod(n) for n = 21224095 and 21224104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224123) by changing a digit.

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, 265262 + ... + 265341.

Almost surely, 2^21224120 is an apocalyptic number.

21224120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21224120 is an abundant number, since it is smaller than the sum of its proper divisors (26530240).

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

21224120 is a wasteful number, since it uses less digits than its factorization.

21224120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530614 (or 530610 counting only the distinct ones).

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

The square root of 21224120 is about 4606.9642933281. The cubic root of 21224120 is about 276.8704229583.

Adding to 21224120 its reverse (2142212), we get a palindrome (23366332).

The spelling of 21224120 in words is "twenty-one million, two hundred twenty-four thousand, one hundred twenty".