My number:
1. Is a 3-digit number.
2. All its digits are prime digits.
3. A number formed by its 1st 2 digits is prime.
4. So is the number formed by its last 2 digits.
5. It is the smallest number satisfying the above conditions.

Find it.

Rem: The digits in my number do not have to be distinct.

I think it's a number that is a two-sided prime, or a number which is both left-truncatable and right-truncatable. The smallest 3-digit number is 313.

Posted by Benny on 2011-12-22 03:02:36