21224042 has 16 divisors (see below), whose sum is σ = 36443520. Its totient is φ = 9081168.

The previous prime is 21224023. The next prime is 21224053. The reversal of 21224042 is 24042212.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21224042.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 14843 + ... + 16209.

It is an arithmetic number, because the mean of its divisors is an integer number (2277720).

Almost surely, 2^21224042 is an apocalyptic number.

21224042 is a deficient number, since it is larger than the sum of its proper divisors (15219478).

21224042 is a wasteful number, since it uses less digits than its factorization.

21224042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2485.

The product of its (nonzero) digits is 256, while the sum is 17.

The square root of 21224042 is about 4606.9558278759. The cubic root of 21224042 is about 276.8700837857.

Adding to 21224042 its reverse (24042212), we get a palindrome (45266254).

The spelling of 21224042 in words is "twenty-one million, two hundred twenty-four thousand, forty-two".