#include<stdio.h>
 
int main()
 
{
 
     int number, sum=0, i=1;
 
     printf("Please enter a number to check perfect number\n");
 
     scanf("%d",&number);
 
 
 
     while(i<number)
 
     {
 
           if(number%i==0)
 
           {
 
               sum=sum+i;
 
           }
 
           i++;
 
     }
 
      if(sum==number)
 
           printf("\nEntered number %d is a perfect number",i);
 
     else
 
          printf("\nEntered number %d is not a perfect number",i);
 
     return 0;
 
}

Output:

Please enter a number to check perfect number

28

Entered number 28 is a perfect number