Armstrong Number in Python

What is an Armstrong Number?

An Armstrong number (or narcissistic number) in a given number base is a number that equals the sum of its own digits, each raised to the power of the number of digits. These numbers are a fascinating concept in number theory and a common starting point for beginners in programming. For example, in base 10:

Example:

153 = 1³ + 5³ + 3³ = 153

Key Properties:

• An Armstrong number can exist in any number base.
• In base 10, single-digit numbers (0 and 1) are considered Armstrong numbers.

Armstrong Number Examples

Here are some examples of Armstrong numbers in the decimal system:

• 3-Digit Numbers:
  • 153: 1³ + 5³ + 3³ = 153
  • 370: 3³ + 7³ + 0³ = 370
  • 371: 3³ + 7³ + 1³ = 371
  • 407: 4³ + 0³ + 7³ = 407
• 4-Digit Numbers:
  • 1634: 1⁴ + 6⁴ + 3⁴ + 4⁴ = 1634
  • 8208: 8⁴ + 2⁴ + 0⁴ + 8⁴ = 8208
  • 9474: 9⁴ + 4⁴ + 7⁴ + 4⁴ = 9474

Armstrong Numbers in Base 3

Even in other bases, Armstrong numbers exist. For example: 122 (base 3) = 1³ + 2³ + 2³ = 17 (decimal).

How to Check for Armstrong Numbers?

To determine whether a number is an Armstrong number, follow this algorithm:

Algorithm:

1. Input: Take the number to be checked.
2. Find Digits: Determine the number of digits (“n”).
3. Process Each Digit:
   • Extract each digit using modulus (num % 10).
   • Raise the digit to the power of “n”.
   • Add the result to a running total.
   • Divide the number by 10 to move to the next digit.
4. Compare: If the total equals the original number, it’s an Armstrong number.

Example Algorithm in Python:

num = int(input("Enter a number: "))
original = num
sum = 0
n = len(str(num))

while num > 0:
    digit = num % 10
    sum += digit ** n
    num //= 10

if sum == original:
    print(f"{original} is an Armstrong Number!")
else:
    print(f"{original} is not an Armstrong Number.")

Output Example:

Enter a number: 153

153 is an Armstrong Number!

Python Programs for Armstrong Numbers

Check a Specific Number:

num = int(input("Enter a number: "))
original = num
sum = 0
n = len(str(num))

while num > 0:
    digit = num % 10
    sum += digit ** n
    num //= 10

if sum == original:
    print(f"{original} is an Armstrong Number.")
else:
    print(f"{original} is not an Armstrong Number.")

Output Example:

Enter a number: 123

123 is not an Armstrong Number.

Find Armstrong Numbers in a Range:

t1 = int(input("Enter the minimum value: "))
t2 = int(input("Enter the maximum value: "))

print("Armstrong numbers in the range:")
for num in range(t1, t2 + 1):
    original = num
    sum = 0
    n = len(str(num))

    while num > 0:
        digit = num % 10
        sum += digit ** n
        num //= 10

    if sum == original:
        print(original)

Output Example:

Enter the minimum value: 100

Enter the maximum value: 500

Armstrong numbers in the range: 153, 370, 371, 407

Print the First “N” Armstrong Numbers:

N = int(input("Enter the number of Armstrong numbers to find: "))
count = 0
num = 1

print("The first", N, "Armstrong numbers are:")
while count < N:
    original = num
    sum = 0
    n = len(str(num))

    while num > 0:
        digit = num % 10
        sum += digit ** n
        num //= 10

    if sum == original:
        print(original)
        count += 1

    num += 1

Output Example:

Enter the number of Armstrong numbers to find: 5

The first 5 Armstrong numbers are: 1, 153, 370, 371, 407

Conclusion

In this blog, we explored the concept of Armstrong numbers, their properties, examples, and Python implementations. Armstrong numbers may not have real-world applications but are a fun and educational topic for programming practice. For more tutorials on Python and machine learning, stay tuned!

Also Read:

• Prime Numbers Program In Python
• How To Add Python To Path?
• Python __init__