Here is a simple and free online Armstrong number calculator to check if a given number is a Narcissistic Number and an Armstrong Number. An Armstrong number is a narcissistic number, whose sum of its digits each raised to the power of the number of digits is equal to the number. A Narcissistic number, is also known as a pluperfect digital invariant (PPDI). For example, 153 is an Armstrong number since 13 + 53 + 33 = 153. In the calculator here enter a number to check if the given number is a Narcissistic Number.