In an **Armstrong** number (also known as *narcissistic number*), is a number that is the sum of its own digits each raised to the power of the number of digits.

xy...z = x^n + y^n + ... + z^n

where n is the number of digits in a number.

Few examples are: 153, 371, 407, 8208, etc.

153 = 1^{3} + 5^{3} + 3^{3}

8208 = 8^{4} + 2^{4} + 0^{4} + 8^{4}