2011 is a prime year. The last three digits of 2011 are 011. If you put any digit from 0 to 9 in front of 011, then your number will either be prime or divisible by 3.
0011=11=prime
1011=3*337
2011=prime
3011=prime
4011=3*7*191
5011=prime
6011=prime
7011=3^2*19*41
8011=prime
9011=prime
What other 3-digit number has the property that if you put any digit from 0 to 9 in front of it, then it will either be prime or divisible by 3?