Smith Number
Smith
numbers are the numbers whose sum
of digits is equal to the sum of the
digits of its prime factor.
Example,
666
prime
factor (2,3,3,37) = 2+3+3+3+7 = 18
sum
of digits 6 + 6 + 6 = 18.
//4,
22, 319, 346, 636,666,1086
import
java.io.*;
class Smith_No
{
public static void main(String
args[])throws IOException
{
Smith_No sm=new Smith_No();
BufferedReader Br=new
BufferedReader(new InputStreamReader(System.in));
int n,num,s,sum=0,f,i=2;
System.out.print("\n\tEnter a Number : ");
n=Integer.parseInt(Br.readLine());
num=n;
s=sm.sep(n);
while(n>1)
{
f=0;
if(n%i==0)
{
n=n/i;
if(sm.prime(i))
{
sum=sum+sm.sep(i);;
}
}
else
{
i++;
}
}
if(s==sum)
{
System.out.println("\n\t"+num+" is a Smith
Number");
}
else
{
System.out.println("\n\t"+num+" is not a Smith
Number");
}
}
boolean prime(int n)
{
int i;
for(i=2;i<=n/2;i++)
{
if(n%i==0)
return false;
}
return true;
}
int sep(int n)
{
int s=0;
while(n>0)
{
s=s+n%10;
n=n/10;
}
return s;
}
}
Output
Enter a Number : 666
666 is a Smith Number
Enter a Number : 456
456 is Not a Powerful Number
Powerful Number
A
powerful number is a positive integer that the square of each prime factor also
be a factor of the number.
Example.
9
prime
factor of 9 = 3 where 32 also a factor of the number
factor
of 81 is 3,9 and 32 and 92 also facor of 81.
//4,
8, 9, 16, 100, 225, 243, 972, 1000
import
java.io.*;
public class Powerful_No
{
public static void main(String
args[]) throws IOException
{
BufferedReader Br=new
BufferedReader(new InputStreamReader(System.in));
int n,i=2,j;
Powerful_No PN=new
Powerful_No();
boolean flag=true;
System.out.print("\n\tEnter a Number : ");
n=Integer.parseInt(Br.readLine());
for(j=2;j<=n/2;j++)
{
if(n%j==0)
{
if(PN.isPrime(j))
{
if(n%(j*j)!=0)
{
flag=false;
break;
}
}
}
}
if(flag)
{
System.out.print("\n\t"+n+" is a Powerful Number");
}
else
{
System.out.print("\n\t"+n+" is Not a Powerful
Number");
}
}
// Checking for Prime Numbers
boolean isPrime(int n)
{
int i;
for(i=2;i<=n/2;i++)
{
if(n%i==0)
return false;
}
return true;
}
}
Output
Enter a Number : 81
81 is a Powerful Number
Enter a Number : 38
38 is Not a Powerful Number
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