Write a Python program that takes a positive integer as input and checks if the number is narcissistic or not. A narcissistic number is a number that is the sum of its own digits each raised to the power of the number of digits. The program should output "True" if the number is narcissistic and "False" if it is not. The program should also handle cases where the input is not a positive integer, and should prompt the user to enter a valid input if necessary. The program should be written in a clear and concise style, with appropriate variable names and comments to explain the logic.
This prompt doesn't seem malicious.