A Prime Factors of a given number is that any prime number other than 1 and itself that exactly divides the given number. For example, the prime factors of 60 is 2, 3, 5

Examples

The following table provides few examples of prime factors of a number.

Number

Prime Factors

55

5, 11

100

2, 5

186

2, 3, 31

Find Prime Factor

In the following example, we will find all the Prime factors of the given number (186).

Example

C# Compiler

using System;
namespace myApp
{
class Program
{
static void Main(string[] args)
{
int num =186;
int i, j;
int count =0;
int flag =0;
Console.Write("Prime factor of {0}:\n", num);
for(i=2; i<num; i++)
{
// check for divisibilityif(num % i ==0)
{
count =0;
// check for prime numberfor(j=1; j<=i; j++)
{
if(i % j ==0)
count++;
}
if(count ==2)
{
flag =1;
Console.Write(i +" ");
}
}
}
if(flag ==0)
Console.Write("There is no Prime factor for {0} ", num);
}
}
}

Output

Prime factor of 186:
2 3 31

Find Prime Factor of any Given Number

In the following example, we will find a prime factors of any given number.

Example

C# Compiler

using System;
namespace myApp
{
class Program
{
static void Main(string[] args)
{
Console.Write("Enter a (int) Number: ");
int num = Convert.ToInt32(Console.ReadLine());
int i, j;
int count =0;
int flag =0;
Console.WriteLine("\nPrime factor of {0}: ", num);
for(i=2; i<num; i++)
{
// check for divisibilityif(num % i ==0)
{
count =0;
// check for prime numberfor(j=1; j<=i; j++)
{
if(i % j ==0)
count++;
}
if(count ==2)
{
flag =1;
Console.Write(i +" ");
}
}
}
if(flag ==0)
Console.Write("There is no Prime factor for {0} ", num);
}
}
}

Output

Enter a (int) Number: 25
Prime factor of 25:
5

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