22224721 has 2 divisors, whose sum is σ = 22224722. Its totient is φ = 22224720.

The previous prime is 22224707. The next prime is 22224743. The reversal of 22224721 is 12742222.

It is a happy number.

It is an a-pointer prime, because the next prime (22224743) can be obtained adding 22224721 to its sum of digits (22).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20151121 + 2073600 = 4489^2 + 1440^2 .

It is a cyclic number.

It is not a de Polignac number, because 22224721 - 2⁵ = 22224689 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 22224692 and 22224701.

It is not a weakly prime, because it can be changed into another prime (22224781) 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 as a sum of consecutive naturals, namely, 11112360 + 11112361.

It is an arithmetic number, because the mean of its divisors is an integer number (11112361).

Almost surely, 2^22224721 is an apocalyptic number.

It is an amenable number.

22224721 is a deficient number, since it is larger than the sum of its proper divisors (1).

22224721 is an equidigital number, since it uses as much as digits as its factorization.

22224721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 896, while the sum is 22.

The square root of 22224721 is about 4714.3102358670. The cubic root of 22224721 is about 281.1547591263.

Adding to 22224721 its reverse (12742222), we get a palindrome (34966943).

The spelling of 22224721 in words is "twenty-two million, two hundred twenty-four thousand, seven hundred twenty-one".