A number is squared. The result is squared, then that result is squared. The final number is 6561

The question is saying a number is square, then squared again, and finally square again, making that number squared itself up to 3 times. So we take 6561 and we square root it 3 times. Square root of 6561 is 81, square of 81 is 9, and finally square root if 9 is 3. The final answer is 3.