The number 17 is an example of a prime number that remains prime when you reverse its digits (that is, 71 is also prime). Which of the following prime numbers also has this property?
(A) 29
(B) 53
(C) 23
(D) 13
(E) 41
If the tens digit of a two-digit number is even, then when the digits are reversed the new number will have a units digit that is even and therefore the number will be even.

If a two-digit number is even, then it is divisible by 2 and so it cannot be a prime number.

Since 29, 23 and 41 each have a tens digit that is even, we may eliminate these three as possible answers.

When the digits of 53 are reversed, the result is 35 .

Since 35 is divisible by 5 , it is not a prime number.

Finally, when the digits of 13 are reversed, the result is 31 .

Since 31 has no positive divisors other than 1 and 31 , it is a prime number.

ANSWER: (D)