Answers

2015-06-02T19:20:36+05:30
Because it has only 1 factor that is itself only 1
other numbers have 2 factors : 1. number itself
                                               2.one
1 5 1
2015-06-02T19:21:10+05:30
1 is not a prime number because it does not have factors other than 1.
       ex:1x1 
             so,it not a prime number.....
1 5 1