211122222111221 has 2 divisors, whose sum is σ = 211122222111222. Its totient is φ = 211122222111220.

The previous prime is 211122222111211. The next prime is 211122222111223. The reversal of 211122222111221 is 122111222221112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 203737084322500 + 7385137788721 = 14273650^2 + 2717561^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211122222111221 is a prime.

It is a super-2 number, since 2×211122222111221² (a number of 29 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 211122222111223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211122222111223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105561111055610 + 105561111055611.

It is an arithmetic number, because the mean of its divisors is an integer number (105561111055611).

Almost surely, 2^{211122222111221} is an apocalyptic number.

It is an amenable number.

211122222111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

211122222111221 is an equidigital number, since it uses as much as digits as its factorization.

211122222111221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 256, while the sum is 23.

Adding to 211122222111221 its reverse (122111222221112), we get a palindrome (333233444332333).

The spelling of 211122222111221 in words is "two hundred eleven trillion, one hundred twenty-two billion, two hundred twenty-two million, one hundred eleven thousand, two hundred twenty-one".