211111212110221 has 2 divisors, whose sum is σ = 211111212110222. Its totient is φ = 211111212110220.

The previous prime is 211111212110213. The next prime is 211111212110243. The reversal of 211111212110221 is 122011212111112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 185594711589225 + 25516500520996 = 13623315^2 + 5051386^2 .

It is a cyclic number.

It is not a de Polignac number, because 211111212110221 - 2³ = 211111212110213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211111212110021) 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, 105555606055110 + 105555606055111.

It is an arithmetic number, because the mean of its divisors is an integer number (105555606055111).

Almost surely, 2^{211111212110221} is an apocalyptic number.

It is an amenable number.

211111212110221 is a deficient number, since it is larger than the sum of its proper divisors (1).

211111212110221 is an equidigital number, since it uses as much as digits as its factorization.

211111212110221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 19.

Adding to 211111212110221 its reverse (122011212111112), we get a palindrome (333122424221333).

The spelling of 211111212110221 in words is "two hundred eleven trillion, one hundred eleven billion, two hundred twelve million, one hundred ten thousand, two hundred twenty-one".