211671221221 has 2 divisors, whose sum is σ = 211671221222. Its totient is φ = 211671221220.

The previous prime is 211671221197. The next prime is 211671221239. The reversal of 211671221221 is 122122176112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 178494420196 + 33176801025 = 422486^2 + 182145^2 .

It is a cyclic number.

It is not a de Polignac number, because 211671221221 - 2¹⁵ = 211671188453 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 211671221221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211671221621) 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, 105835610610 + 105835610611.

It is an arithmetic number, because the mean of its divisors is an integer number (105835610611).

Almost surely, 2^211671221221 is an apocalyptic number.

It is an amenable number.

211671221221 is a deficient number, since it is larger than the sum of its proper divisors (1).

211671221221 is an equidigital number, since it uses as much as digits as its factorization.

211671221221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1344, while the sum is 28.

Adding to 211671221221 its reverse (122122176112), we get a palindrome (333793397333).

The spelling of 211671221221 in words is "two hundred eleven billion, six hundred seventy-one million, two hundred twenty-one thousand, two hundred twenty-one".