222009721 has 2 divisors, whose sum is σ = 222009722. Its totient is φ = 222009720.

The previous prime is 222009679. The next prime is 222009727. The reversal of 222009721 is 127900222.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 220938496 + 1071225 = 14864^2 + 1035^2 .

It is a cyclic number.

It is not a de Polignac number, because 222009721 - 2¹⁷ = 221878649 is a prime.

It is not a weakly prime, because it can be changed into another prime (222009727) by changing a digit.

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 as a sum of consecutive naturals, namely, 111004860 + 111004861.

It is an arithmetic number, because the mean of its divisors is an integer number (111004861).

Almost surely, 2^222009721 is an apocalyptic number.

It is an amenable number.

222009721 is a deficient number, since it is larger than the sum of its proper divisors (1).

222009721 is an equidigital number, since it uses as much as digits as its factorization.

222009721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 222009721 is about 14899.9906375810. The cubic root of 222009721 is about 605.5137325297.

Adding to 222009721 its reverse (127900222), we get a palindrome (349909943).

The spelling of 222009721 in words is "two hundred twenty-two million, nine thousand, seven hundred twenty-one".