Python
# Program to check Armstrong number (order 3)
num = int(input("Enter an integer: "))
digits = str(num)
power = len(digits)
total = 0
for d in digits:
total += int(d) ** power
if total == num:
print(num, "is an Armstrong number")
else:
print(num, "is not an Armstrong number")Output
Enter an integer: 153 153 is an Armstrong number
An Armstrong number is equal to the sum of its digits each raised to the power of the number of digits. We convert the number to a string to iterate over digits, then compare the sum with the original number.