Abundant Number or Not in C Program

September 28, 2022

Abundant Number in C

In this program, we need to check if a number is an Abundant number in C Programming. A number n is said to be Abundant Number to follow these condition

  • The sum of its proper divisors is greater than the number itself
  • The difference between these two values is called the abundance.
Ex:- Abundant number  12 having a proper divisor is 1, 2, 3, 4, 6 

The sum of these factors is 16 it is greater than 12 
So it is an Abundant number

Some other abundant numbers: 

18, 20, 30, 70, 78, 80, 84, 90, 96, 100, 104, 108, 120
abundant or not in c

Working:-

For user input num

  • Find all proper divisors of num
  • Calculate the sum of these divisors
  • If sum > num : Abundant number
  • Else, not an Abundant number

Method 1 

For user input num
  • Initialize sum = 0
  • Run a loop in the iteration of (i)
  • For each, i check if it is a divisor of num (num % i == 0)
  • If yes then add to the sum
  • Compare sum and num, if sum > num then its abundant number

Method 1 Code

Run 
#include <stdio.h>

int main ()
{
    int num = 18, sum = 0;
    
    for(int i = 1; i < num; i++)
    {
        if(num % i == 0) 
            sum = sum + i; 
    }
if(sum > num){
 printf("%d is an Abundant Number\n",num);
 printf("Num: %d\nSum: %d\nAbundance: %d", num, sum, (sum-num)); 
} else
 printf("%d is not a Abundant Number",num); 
} 
// Time complexity: O(N) 
// Space complexity: O(1)

Output:-

18 is an Abundant Number
Num: 18
Sum: 21
Abundance: 3
While loop in C

Strong number

Perfect number

Harshad number

Automorphic number

Friendly pair

Method 2

This method uses observations that all factors come in pairs.

Method 2 Code

Run 
#include <stdio.h> 
#include <math.h>
int getSum(int num){
    
    int sum = 0;
    
    for(int i = 1; i < sqrt(num); i++)
    {
        if (num % i == 0)
        {
            // For num : (1, num) will always be pair of divisor
            // acc to def., we must ignore adding num itself as divisor
            // when calculating for abundant number
            if(i == 1)
                sum = sum + i;
            
            // Example For 100 (10,10) will be one of the pair
            // But, we should add value 10 to the sum just once
            else if(i == num/i)
                sum = sum + i;
            
            // add both pairs as divisors
            // For any divisor i, num/i will also be a divisor
            else
                sum = sum + i + num/i;
        }
    }
    return sum;
}

//main Program
int main()
{
    int num=10;
    
  
    
    int sum = getSum(num);
    if(sum > num)
    {
        printf("%d is an Abundant Number\n",num);
        printf("Num: %d\nSum: %d\nAbundance: %d", num, sum, (sum-num));
    }
    else
        printf("%d is not a Abundant Number",num);
}
// Time Complexity: O(√N)
// Space Complexity: O(1)

Output:-

Enter a positive number: 100
100 is an Abundant Number
Num: 100
Sum: 107
Abundance: 7

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While loop in C

2 comments on “Abundant Number or Not in C Program”


  • Srikanth

    n=int(input(“Enter a number : “))
    sum=0
    for i in range(1,n-1):
    if n%i==0:
    sum=sum+i
    print(“sum is”,sum)
    print(“Input is ” , n)
    if sum>n:
    print(“Abandant Number”)
    else:
    print(“Not abandant number “)


  • Mohammed Monis

    Abundant number in Python
    n = int(input(“Enter a number : “))
    factors = []
    for i in range(1, n + 1):
    if n % i == 0:
    factors.append(i)
    sum = 0
    l = len(factors)
    for i in factors[:l – 1]:
    sum = sum + i
    if n < sum :
    print(f"{n} is an abundant number ")
    else:
    print(f"{n} is not an abundant number ")