An Emirp number is a number which is prime backwards and forwards. Now write a program to check a number is Emirp number or not.
If we write the word "prime" backward, then it generate a word called "Emirp". Emirp number is refers to a prime number that becomes a prime number when we reverse its digits. but the palindrom prime numbers are not included as Emirps(like 151 or 787) nor 1-digit primes like 7.
Example: 13 is an Emirp number since 13 and 31 are both prime numbers. Some others examples are 17, 107, 113, 149, and 157
import java.util.*; public class Emirp { public boolean IsPrime(int i) { boolean b=true; int d=2; while(d<i/2) { if (i%d==0) { b=false; break; } d++; } return b; } public static void main(String []args) { int i,r1=3,r2=100; Emirp ep=new Emirp(); Scanner sc=new Scanner(System.in); System.out.print("Enter A Number : "); int no=sc.nextInt(); int fr=no; int rev=0; while(no>0) { rev = (rev*10) + (no%10); no /= 10; } if(ep.IsPrime(fr) && ep.IsPrime(rev)) { System.out.print(fr + " is a Emirp Number"); } else { System.out.print(fr + " is not a Emirp Number"); } } }
Enter A Number : 17
17 is a Emirp Number
Enter A Number : 51
51 is not a Emirp Number