"""
== Krishnamurthy Number ==
It is also known as Peterson Number
A Krishnamurthy Number is a number whose sum of the
factorial of the digits equals to the original
number itself.
For example: 145 = 1! + 4! + 5!
So, 145 is a Krishnamurthy Number
"""
def factorial(digit: int) -> int:
"""
>>> factorial(3)
6
>>> factorial(0)
1
>>> factorial(5)
120
"""
return 1 if digit in (0, 1) else (digit * factorial(digit - 1))
def krishnamurthy(number: int) -> bool:
"""
>>> krishnamurthy(145)
True
>>> krishnamurthy(240)
False
>>> krishnamurthy(1)
True
"""
factSum = 0
duplicate = number
while duplicate > 0:
duplicate, digit = divmod(duplicate, 10)
factSum += factorial(digit)
return factSum == number
if __name__ == "__main__":
print("Program to check whether a number is a Krisnamurthy Number or not.")
number = int(input("Enter number: ").strip())
print(
f"{number} is {'' if krishnamurthy(number) else 'not '}a Krishnamurthy Number."
)