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Python program to find all Strong Numbers in given list
  • Difficulty Level : Hard
  • Last Updated : 24 Jun, 2019

Given a list, write a Python program to find all the Strong numbers in a given list of numbers.

A Strong Number is a number that is equal to the sum of factorial of its digits.


Input : [1, 2, 5, 145, 654, 34] 
Output : [1, 2, 145]

Input : [15, 58, 75, 675, 145, 2]
Output : [145, 2]

Explanation :

  • We defined 2 functions here: First is factorial() and second is strong_number().
  • As soon as strong_number() is called, the list is passed to the function and stored in the formal argument list.
  • For loop iterates for every element in list, temp is a temporary variable on which calculation is done, then factorial() function is called on the remainder of temp mod 10 and passed it to the factorial function.
  • Now when temp equates to 0, it exits the while loop and checks whether sum is equal to x or not. If True then it is added in the list using append() function which is predefined for list and is used to add elements in the list and if there is no strong number then it will return an empty list.

Below is the Python implementation:





# Python program to find all 
# Strong Numbers in given list
def factorial(number):
    if(number == 0 or number == 1):
        fact = 1
        fact = number * factorial(number - 1)
    return fact
def strong_number(list):
    new_list =[]
    for x in list:
        temp = x
        sum = 0
            rem = temp % 10
            sum += factorial(rem)
            temp = temp // 10
        if(sum == x):
    return new_list
# Driver Code
val_list = [1, 2, 5, 145, 654, 34]
strong_num_list = strong_number(val_list)



[1, 2, 145]

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