Python program to find number of integers which has exactly x divisors

October 1, 2022

Number of integers which has exactly x divisors in python

Here, in this page we will discuss the program that count the number of integers which has exactly x divisors in python . Numbers dividing with self or 1 are called prime numbers but numbers having multiple divisors are called composite numbers.

Here, in this page we will discuss the two different ways for finding the required count of numbers that have exactly x divisors. These two methods are given below,

Method 1 : Naive approach
Method 2 : Efficient approach

Method 1 :

Declare a variable count =0, to count the required numbers with x factors.
Run a loop for range 1 to n.
Inside that take a variable count_factors = 0, that will count the factors of i^th.
Now, run a inner loop.
And increase the count_factors if it’s is factor of i^th number.
Check if count_factors == X, then increment the count by 1.
At last print the count value.

Method 1 : Code in Python

Run

Number = 7
Divisor = 2
#count is to count total number of Numbers with exact divisor
count = 0
#driver loop
for i in range(1,Number+1):
    #count_factors checks the total number of divisors
    count_factors = 0
    #loop to find number of divisors
    for j in range(1,i+1):
        if i % j == 0:
            count_factors += 1
        else:
            pass
    if count_factors == Divisor:
        count +=1

#for break in line between Numbers and total count
print(count)

Output :

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Finding Number of times x digit occurs in a given input

Finding Roots of a quadratic equation

Power of a Number

Prime Number

Method 2 :

In this method we will use the efficient way for counting the factors that used in method 1. We use the sieve of eratosthenes for counting the factors.

Method 2 : Code in Python

Run

import math;

def sieve(primes, x):
    primes[1] = False;
     
    i = 2;
    while (i * i <= x):
        if (primes[i] == True):
            j = 2;
            while (j * i <= x):
                primes[i * j] = False;
                j += 1;
        i += 1;
 
def nDivisors(primes, x, a, b, n):
     
    result = 0;
 
    v = [];
    for i in range(2, x + 1):
        if (primes[i]):
            v.append(i);
 

    for i in range(a, b + 1):
        
        temp = i;
 
        total = 1;
        j = 0;
 
        k = v[j];
        while (k * k <= temp):
             
            count = 0;
 
            while (temp % k == 0):
                count += 1;
                temp = int(temp / k);
 
            total = total * (count + 1);
            j += 1;
            k = v[j];
 
        if (temp != 1):
            total = total * 2;
 
        if (total == n):
            result += 1;
    return result;
 
def countNDivisors(a, b, n):
    x = int(math.sqrt(b) + 1);
 
    primes = [True] * (x + 1);
    sieve(primes, x);
 
    return nDivisors(primes, x, a, b, n);
 
n = 7;
x = 2;
print(countNDivisors(1, n, x));

Output :

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11 comments on “Python program to find number of integers which has exactly x divisors”

yogesh
C++ solution

#include

using namespace std;

bool isPrime(int n);

void Numberwith(int n)
{

for (int i = 2; i * i <= n; i++)
{

if (isPrime(i))
{

if (i * i <= n)
{
cout << i * i << " ";
}
}
}
}

bool isPrime(int n)
{

if(n==0 || n==1 )
{
return false;
}

for (int i = 2; i * i > n;
Numberwith(n);
return 0;
}

0

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Shubham
public class JavaApplication1
{
public static void main(String[] args)
{
Scanner obj = new Scanner(System.in);
int n,x;
n = obj.nextInt();
x = obj.nextInt();
for(int i=1;i<=n;i++)
{
int c=0;
String s="";
for(int j=1;j”+s);
System.out.println();
}
}
}
}

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Shubham
public class JavaApplication1
{
public static void main(String[] args)
{
Scanner obj = new Scanner(System.in);
int n,x;
n = obj.nextInt();
x = obj.nextInt();
for(int i=1;i<=n;i++)
{
int c=0;
String s="";
for(int j=1;j”+s);
System.out.println();
}
}
}
}

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Shubham
public class JavaApplication1
{
public static void main(String[] args)
{
Scanner obj = new Scanner(System.in);
int n,x;
n = obj.nextInt();
x = obj.nextInt();
for(int i=1;i<=n;i++)
{
int c=0;
String s="";
for(int j=1;j”+s);
System.out.println();
}
}
}
}

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Om Prakash
Code in Java :
import java.util.Scanner;
public class Exactly_n_divisors
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.print(“Enter range: “);
int range = sc.nextInt();
System.out.print(“Enter exact number of divisors: “);
int exact = sc.nextInt();
int total = 0;
System.out.println(“Numbers which has exactly “+exact+ ” divisors are “);
for(int number=1; number<=range; number++)
{
int count = 0;
for(int divisor=1; divisor<=number; divisor++)
{
if(number%divisor == 0)
count++;
}
if(count == exact)
{
System.out.println(number+" ");
total++;
}
}
System.out.println("Total numbers: "+total);
}
}

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Pankaj Kumar
/* c++ program to find number of integers in given range, which has exactly x divisors */
#include
using namespace std;
int main()
{
int count=0,count1=0,n,x;
/*input range*/
cout<>n;
/*input number of divisors*/
cout<>x;
for (int i=1;i<=n;i++)
{
count1=0;
for (int j=1;j<=i;j++)
{
if (i%j==0)
{
count1++;
}
}
if (count1==x)
{
count++;
/*printing the integers wich has exactly x divisors */
cout<<i<<" ";
}
}
/* printing the total number of integers in the range which has exactly x divisors */
cout<<"\n"<<count;
return 0;
}

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Pankaj Kumar
/* c++ program to find number of integers in a given range, which has exactly x divisors */

#include

using namespace std;

int main()

{

int count=0 ,count1=0, n, x;

// input range

cout<>n;

// input number of divisors

cout<>x;

for (int i=1; i<=n; i++)

{

count1=0;

for (int j=1; j<=i; j++)

{

if (i%j==0)

{
count1++;
}

}

if (count1==x)

{

count++;

// printing the integers ( in given range ) which has exactly x divisors

cout<<i<<" ";

}

}

// printing the total number of integers in the range which has exactly x divisors

cout<<"\n"<<count;

return 0;

}

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placement
program in c:—->
void main()
{
int n,x,count=0,i=0,a[10],j;
printf(“enter the range”);
scanf(“%d”,&n);
printf(“enter the exact divisor”);
scanf(“%d”,&x);
for(i=1;i<=n;i++)
{
count=0;
for(j=1;j=0)
{
printf(“%d\t”,a[i]);
i–;
}
}

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placement
program in c:—–

#include
void main()
{
int n,x,count=0,i=0,a[10],j;
printf(“enter the range”);
scanf(“%d”,&n);
printf(“enter the exact divisor”);
scanf(“%d”,&x);
for(i=1;i<=n;i++)
{
count=0;
for(j=1;j=0)
{
printf(“%d\t”,a[i]);
i–;
}
}

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shailendra
// in c
#include

int main()
{
int n,i,c=0,d;
printf(“enter last range number:”);
scanf(“%d”,&n);
printf(“enter exactly n divisor:”);
scanf(“%d”,&d);
for( i=1;i<=n;i++)

{ int count=0;
for(int j=1;j<=i;j++)
{
if(i%j==0)
{ //printf("%d\t",i);
count++;
}
}
if(count==d)
{
c++;
printf("%d\t",i);
}
}
printf("\n%d",c);

return 0;
}

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Shubham Kumar
#program in java

import java.util.*;
public class EqualDivisorInRange {

public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println(“Enter range: “);
int r=sc.nextInt();
System.out.println(“Enter maxm divisor of number: “);
int d=sc.nextInt();
int c[]=new int[r];
int k=0;
for(int i=1;i<=r;i++)
{
int count=0;
for(int j=1;j<=i;j++)
{
if(i%j==0)
{
count++;
}
}
if(count==d)
{
c[k]=i;
k++;
}

}
System.out.println("Number are with equal divisor: ");
for(int p=0;p<k;p++)
{
System.out.println(c[p]);
}
}

}

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