Add Disarium number checker implementation

DIRECTORY.md

@@ -777,6 +777,7 @@
     * [Bell Numbers](maths/special_numbers/bell_numbers.py)
     * [Carmichael Number](maths/special_numbers/carmichael_number.py)
     * [Catalan Number](maths/special_numbers/catalan_number.py)
+    * [Disarum Number](maths/special_numbers/disarum_number.py)
     * [Hamming Numbers](maths/special_numbers/hamming_numbers.py)
     * [Happy Number](maths/special_numbers/happy_number.py)
     * [Harshad Numbers](maths/special_numbers/harshad_numbers.py)

maths/special_numbers/disarum_number.py

@@ -0,0 +1,51 @@
+"""
+A number n is said to be a Disarium number if
+the sum of its digits powered to their respective positions equals the number itself.
+
+Examples of Disarium Numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, 89, 135, 175, 518, 598, ...
+"""
+
+
+def is_disarium_number(number: int) -> bool:
+    """
+    This function takes an integer number as input.
+    Returns True if the number is a Disarium number.
+
+    >>> is_disarium_number(-1)
+    False
+    >>> is_disarium_number(0)
+    False
+    >>> is_disarium_number(1)
+    True
+    >>> is_disarium_number(89)
+    True
+    >>> is_disarium_number(135)
+    True
+    >>> is_disarium_number(175)
+    True
+    >>> is_disarium_number(518)
+    True
+    >>> is_disarium_number(598)
+    True
+    >>> is_disarium_number(123)
+    False
+    >>> is_disarium_number(89.0)
+    Traceback (most recent call last):
+        ...
+    TypeError: Input value of [number=89.0] must be an integer
+    """
+    if not isinstance(number, int):
+        msg = f"Input value of [number={number}] must be an integer"
+        raise TypeError(msg)
+    if number < 1:
+        return False
+
+    digits = str(number)
+    total = sum(int(digit) ** (idx + 1) for idx, digit in enumerate(digits))
+    return total == number
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()