1211221111171 has 2 divisors, whose sum is σ = 1211221111172. Its totient is φ = 1211221111170.

The previous prime is 1211221111151. The next prime is 1211221111181. The reversal of 1211221111171 is 1711111221121.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (1711111221121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1211221111171 - 2¹³ = 1211221102979 is a prime.

It is not a weakly prime, because it can be changed into another prime (1211221111151) 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, 605610555585 + 605610555586.

It is an arithmetic number, because the mean of its divisors is an integer number (605610555586).

Almost surely, 2^{1211221111171} is an apocalyptic number.

1211221111171 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211221111171 is an equidigital number, since it uses as much as digits as its factorization.

1211221111171 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56, while the sum is 22.

Adding to 1211221111171 its reverse (1711111221121), we get a palindrome (2922332332292).

The spelling of 1211221111171 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, one hundred eleven thousand, one hundred seventy-one".