21224448 has 198 divisors, whose sum is σ = 72807696. Its totient is φ = 5935104.

The previous prime is 21224447. The next prime is 21224479. The reversal of 21224448 is 84442212.

21224448 is a `hidden beast` number, since 212 + 2 + 4 + 448 = 666.

It is a Cunningham number, because it is equal to 4607²-1.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224447) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 451561 + ... + 451607.

Almost surely, 2^21224448 is an apocalyptic number.

21224448 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21224448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36403848).

21224448 is an abundant number, since it is smaller than the sum of its proper divisors (51583248).

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

21224448 is a wasteful number, since it uses less digits than its factorization.

21224448 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87 (or 59 counting only the distinct ones).

The product of its digits is 4096, while the sum is 27.

The square root of 21224448 is about 4606.9998914695. Note that the first 3 decimals coincide. The cubic root of 21224448 is about 276.8718492135.

The spelling of 21224448 in words is "twenty-one million, two hundred twenty-four thousand, four hundred forty-eight".