Python program to check whether two numbers are Friendly Pair

September 28, 2022

Check Whether or Not the Two Numbers are Friendly Pairs in Python

Given two integer numbers as the input, the objective is to check whether or not the two numbers are Friendly pairs of each other. Therefore, we’ll write a Program to Check Whether or Not the Two Numbers are Friendly Pairs in Python.

Example
Input : 6 28
Output : Yes, they are a friendly pair

Check Whether or Not the Two Numbers are Friendly Pairs in Python Language

Given two integer inputs as the numbers, the objective is to check whether the (divisors)/number ratio for the both the numbers are same or not. To do so we’ll run a loop to first find all the factors the the two numbers and then we’ll get the ratio using the above mentioned formula. We check whether the ratios are matching or not. Here are some of the methods we’ll use to Check Whether or Not the Two Numbers are Friendly Pairs in Python Language,

Method 1: Using the Range until Number.
Method 2: Using the Range until Sqrt( Number )

We’ll discuss the above mentioned methods in detail in the upcoming sections. Do check the blue box mentioned below for better understanding. Check out the python page to Find all the Factors of a Number for better understanding.

Friendly Pair Numbers The numbers whose ( sum of divisors ) / number ratio is same are known as Friendly Pair Numbers.
Let's try and understand it better using an example

Example
Input : 6 28
Output : Yes, they are a friendly pair
Explanation : The factors of 6 and 28 except the numbers themselves are 1, 2, 3 and 1, 2, 4, 7, 14 respectively.
Now the sum of factors of both the numbers are 6 and 28 respectively. 
When we divide the sums with the numbers we get 1 and 1 respectively. 
As the ratio of both the number match, they are considered as a friendly pair.

Therefore, from the above mentioned definition and example, we'll check for friendly pairs.

Method 1: Using the Range until Number

In this method we’ll check for factors in the range of 2 to the number itself. We’ll define a function that returns all the factors of a given number. Then we’ll sum them up and divide with the number itself to get the required ratio. In the end we’ll do the same for both the numbers and match their ratio.

Python Code

Run

def printDivisors(n, factors) :
    i = 1
    while i <= n :
        if (n % i==0) :
            factors.append(i)
        i = i + 1
    return sum(factors) - n

if __name__ == "__main__": 
  number1, number2 = 6, 28
  if int(printDivisors(number1, [])/number1) == int(printDivisors(number2, [])/number2):
    print("Friendly pair")
  else:
    print("Not a Friendly Pair")

Output

Friendly pair

Method 2: Using the Range until Sqrt( Number )

In this method we’ll use a loop within a function to find all the factors of the given number input. We’ll run the loop from 2 to the square root of the number. Once we get all the factors except the number itself, we’ll sum them all up and divide it with the same number. We’ll do the same for both numbers and match the ratio.

Python Code

Run

def printDivisors(n, factors) :
     
    # Note that this loop runs till square root
    i = 1
    while i <= pow(n,0.5):
         
        if (n % i == 0) :
             
            # If divisors are equal, print only one
            if (n / i == i) :
                factors.append(i)
            else :
                # Otherwise print both
                factors.append(i)
                factors.append(int(n/i))
        i = i + 1
    return sum(factors) - n

if __name__ == "__main__": 
  number1, number2 = 6, 28
  if int(printDivisors(number1, [])/number1) == int(printDivisors(number2, [])/number2):
    print("Friendly pair")
  else:
    print("Not a Friendly Pair")

Output

Friendly Pair

Strong number

Perfect number

Harshad number

Automorphic number

Abundant number

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25 comments on “Python program to check whether two numbers are Friendly Pair”

Thanushree N
def friendly(n):
s=0
for i in range(1,int(n/2)+1):
if n%i==0:
s=s+i
return s
a,b=input().split()
a,b=int(a),int(b)
a1=friendly(a)
a2=friendly(b)
if a1//a==a2//b:
print(“f”)
else:
print(“n”)

0

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PrepInsta Support
Hey, Our mentors can help you with your technical queries on Discord

0

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Abhishek
# Try This
def factors_sum(n):
s=0
for i in range(1,n//2+1):
if n%i==0:
s+=i
return s

a,b=input().split()
a,b=int(a),int(b)
sum_a=factors_sum(a)
sum_b=factors_sum(b)
print(“\nFriendly Pair” if a/sum_a==b/sum_b else “Not a Frendly Pair”)

0

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vamsi
a=int(input(“”))
b=int(input(“”))
s=0
d=0
for i in range(1,a):
if(a%i==0):
s=s+i
for i in range(1,b):
if(b%i==0):
d=d+i
if(a/s==b/d):
print(“yes”)
else:
print(“no”)

3

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yaswanth
num1=6
num2=28
sum1=0
sum2=0
for i in range(1,num1):
if(num1%i==0):
sum1=sum1+i
for i in range(1,num2):
if(num2%i==0):
sum2=sum2+i
if (sum1==num1 and sum2==num2):
print(” friendly pair”)
else:
print(“not friendly pair”)

6

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Sangram
N1, N2 = 6, 28
ls1, ls2 = [i for i in range(1, N1) if N1 % i == 0], [i for i in range(1, N2) if N2 % i == 0]
print(“FriendlyPair” if sum(ls1)/N1==1 and sum(ls2)/N2==1 else “False”)

0

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D
n,m=int(input()),int(input())
s,c=0,0
for i in range(1,n):
if n%i==0:
s+=i
for j in range(1,m):
if m%j==0:
c+=j

if (s/n)==(c/m):
print(“friendly pair”)
else:
print(“not friendly pair”)

0

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Madipadige
a,b=[int(x) for x in input().split()]
c,d= sum([i for i in range(1,a) if a%i==0]),sum([i for i in range(1,b) if b%i==0])
if(c//a==1 and d//b==1):
print(“friendly pair”)
else:
print(“not a friendly pair”)

0

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as138842
n , m = map(int,input(“Give input = “).split())

def allfactors(n):
factors = [1]
for i in range(2, (n // 4) + 2):
if n % i == 0 and i not in factors:
factors.append(i)
if (n // i) not in factors:
factors.append(n // i)
return factors
def isFriendlyPair(num1,num2):
sum1 = sum(allfactors(num1))
sum2 = sum(allfactors(num2))
if sum1/num1 == sum2/num2:
return “Yes this number is a Friendly Pair”
else:
return “No it is not a Friendly Pair”
print(isFriendlyPair(n,m))

0

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cherith
n1=int(input())
n2=int(input(” “))
sum1=0
sum2=0
for i in range(1,n1):
if n1%i==0:
sum1+=i
print(sum1)
for j in range(1,n2):
if n2%j==0:
sum2+=j
print(sum2)
a=sum1/n1
b=sum2/n2
print(a,b)
if a==b:
print(“friendly pairs”)
else:
print(“no”)

0

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AMIT
num1=int(input(“Enter the number: “))
num2=int(input(“Enter the number : “))
def sumfactor(n):
sum=1
for i in range(2,n):
if n%i== 0:
sum = sum + i
return sum

a=sumfactor(num1)
b=sumfactor(num2)

if a/num1 == b/num2 :
print(“It is the friendly pair”)
else:
print(“It is not the friendly pair”)

4

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Ashish
n=int(input(“Enter first Number “))
m=int(input(“Enter Second Number “))
a=0
b=0
for i in range(1,n+1):
if n%i==0:
a=a+i
else:
pass
for i in range(1,m+1):
if m%i==0:
b=b+i
else:
pass
print(a,b)
if a/n==b/m:
print(“Friendly Number”)
else:
print(“Not Friendly Number”)

2

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