1221222122209 has 2 divisors, whose sum is σ = 1221222122210. Its totient is φ = 1221222122208.

The previous prime is 1221222122177. The next prime is 1221222122233. The reversal of 1221222122209 is 9022212221221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1034746700625 + 186475421584 = 1017225^2 + 431828^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221222122209 - 2⁵ = 1221222122177 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221222122009) 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, 610611061104 + 610611061105.

It is an arithmetic number, because the mean of its divisors is an integer number (610611061105).

Almost surely, 2^{1221222122209} is an apocalyptic number.

It is an amenable number.

1221222122209 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221222122209 is an equidigital number, since it uses as much as digits as its factorization.

1221222122209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 28.

It can be divided in two parts, 1221222 and 122209, that added together give a palindrome (1343431).

The spelling of 1221222122209 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-two million, one hundred twenty-two thousand, two hundred nine".