11111221220171 has 2 divisors, whose sum is σ = 11111221220172. Its totient is φ = 11111221220170.

The previous prime is 11111221220159. The next prime is 11111221220237. The reversal of 11111221220171 is 17102212211111.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11111221220171 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (11111221420171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5555610610085 + 5555610610086.

It is an arithmetic number, because the mean of its divisors is an integer number (5555610610086).

Almost surely, 2^{11111221220171} is an apocalyptic number.

11111221220171 is a deficient number, since it is larger than the sum of its proper divisors (1).

11111221220171 is an equidigital number, since it uses as much as digits as its factorization.

11111221220171 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 23.

Adding to 11111221220171 its reverse (17102212211111), we get a palindrome (28213433431282).

The spelling of 11111221220171 in words is "eleven trillion, one hundred eleven billion, two hundred twenty-one million, two hundred twenty thousand, one hundred seventy-one".