6. (10 points) There is a special calculator. When a number is input, the calculator multiplies this number by 2, then reverses the order of the digits of the result, and finally adds 2 to display the final result. If a two-digit number is input, and the final result displayed is 45, then the number initially input was $\qquad$
【Answer】Solution: Reverse operation, the digits of the product in reverse order are: $45-2=43$, then, before reversing it was 34,

The input two-digit number is: $34 \div 2=17$;
Answer: The number initially input was 17.
Therefore, the answer is: 17.