5. (5 points) Dividing 1722 by a two-digit number, Xiao Ming mistakenly reversed the tens and units digits of this number, resulting in the incorrect answer of 42. What should the correct result be? $\qquad$ .
【Analysis】Based on the dividend and the incorrect quotient, find the wrong divisor, then swap the tens and units digits of the wrong divisor to find the correct divisor, and then find the correct quotient.

【Solution】Solution: $1722 \div 42=41$,
so the correct divisor is 14,
$$
1722 \div 14=123 ;
$$

Answer: The correct result should be 123.
Therefore, the answer is: 123.
【Comment】The key to solving this problem is to first find the wrong divisor, then derive the correct divisor, and finally use the dividend $\div$ divisor = quotient.