21224415 has 16 divisors (see below), whose sum is σ = 35957088. Its totient is φ = 10653696.

The previous prime is 21224389. The next prime is 21224431. The reversal of 21224415 is 51442212.

It is not a de Polignac number, because 21224415 - 2⁶ = 21224351 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21224391 and 21224400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41362 + ... + 41871.

It is an arithmetic number, because the mean of its divisors is an integer number (2247318).

Almost surely, 2^21224415 is an apocalyptic number.

21224415 is a deficient number, since it is larger than the sum of its proper divisors (14732673).

21224415 is a wasteful number, since it uses less digits than its factorization.

21224415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83258.

The product of its digits is 640, while the sum is 21.

The square root of 21224415 is about 4606.9963099616. The cubic root of 21224415 is about 276.8717057190.

Adding to 21224415 its reverse (51442212), we get a palindrome (72666627).

The spelling of 21224415 in words is "twenty-one million, two hundred twenty-four thousand, four hundred fifteen".