In this example, We are going to define a user-defined function to check whether the entered number is Armstrong number or not.

A number is known as Armstrong’s number if the sum of the cube root of each digit of this number regenerates the same number again.

Python function to check Armstrong Number

def armstrong(n):
    m = n
    sum = 0
    while(n != 0):
        rem = n % 10
        sum += rem**3
        n = n//10
    return True if sum == m else False

Implementation of armstrong function in a Python Program

if __name__ == "__main__":
    n = int(input('Enter any number :'))
    print('ArmStrong Number ' if(armstrong(n)) else 'Not a Arm Strong Number ')

Hence the whole Python program is

def armstrong(n):
    m = n
    sum = 0
    while(n != 0):
        rem = n % 10
        sum += rem**3
        n = n//10
    return True if sum == m else False


if __name__ == "__main__":
    n = int(input('Enter any number :'))
    print('ArmStrong Number ' if(armstrong(n)) else 'Not a ArmStrong Number ')

Output of the above Program is

Enter any number:6
Not a ArmStrong Number 

Enter any number :153
ArmStrong Number