21224442 has 8 divisors (see below), whose sum is σ = 42448896. Its totient is φ = 7074812.

The previous prime is 21224431. The next prime is 21224447. The reversal of 21224442 is 24442212.

It is a sphenic number, since it is the product of 3 distinct primes.

21224442 is an admirable number.

It is a super-2 number, since 2×21224442² = 900953876422728, which contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 1768698 + ... + 1768709.

It is an arithmetic number, because the mean of its divisors is an integer number (5306112).

Almost surely, 2^21224442 is an apocalyptic number.

21224442 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21224442 is a wasteful number, since it uses less digits than its factorization.

21224442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3537412.

The product of its digits is 1024, while the sum is 21.

The square root of 21224442 is about 4606.9992402865. Note that the first 3 decimals coincide. The cubic root of 21224442 is about 276.8718231236.

Adding to 21224442 its reverse (24442212), we get a palindrome (45666654).

The spelling of 21224442 in words is "twenty-one million, two hundred twenty-four thousand, four hundred forty-two".