211333221721 has 2 divisors, whose sum is σ = 211333221722. Its totient is φ = 211333221720.

The previous prime is 211333221719. The next prime is 211333221733. The reversal of 211333221721 is 127122333112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 210570854400 + 762367321 = 458880^2 + 27611^2 .

It is a cyclic number.

It is not a de Polignac number, because 211333221721 - 2¹ = 211333221719 is a prime.

Together with 211333221719, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 211333221721.

It is not a weakly prime, because it can be changed into another prime (211333221791) 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, 105666610860 + 105666610861.

It is an arithmetic number, because the mean of its divisors is an integer number (105666610861).

Almost surely, 2^211333221721 is an apocalyptic number.

It is an amenable number.

211333221721 is a deficient number, since it is larger than the sum of its proper divisors (1).

211333221721 is an equidigital number, since it uses as much as digits as its factorization.

211333221721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 28.

Adding to 211333221721 its reverse (127122333112), we get a palindrome (338455554833).

The spelling of 211333221721 in words is "two hundred eleven billion, three hundred thirty-three million, two hundred twenty-one thousand, seven hundred twenty-one".