Narcissistic Numbers

by Matt tags: numbers, language_fundamentals, validation

Summary

A number is narcissistic when the sum of its digits, with each digit raised to the power of digits quantity, is equal to the number itself. 153 ➞ 3 digits ➞ 1³ + 5³ + 3³ = 1 + 125 + 27 = 153 ➞ Narcissistic 84 ➞ 2 digits ➞ 8² + 4² = 64 + 16 = 80 ➞ Not narcissistic Given a positive integer n, implement a function that returns true if the number is narcissistic

Instructions

A number is narcissistic when the sum of its digits, with each digit raised to the power of digits quantity, is equal to the number itself.

153 ➞ 3 digits ➞ 1³ + 5³ + 3³ = 1 + 125 + 27 = 153 ➞ Narcissistic
84 ➞ 2 digits ➞ 8² + 4² = 64 + 16 = 80 ➞ Not narcissistic

Given a positive integer n, implement a function that returns true if the number is narcissistic, and false if it's not.

Examples

isNarcissistic(8208) ➞ true
// 8⁴ + 2⁴ + 0⁴ + 8⁴ = 8208

isNarcissistic(22) ➞ false
// 2² + 2² = 8

isNarcissistic(9) ➞ true
// 9¹ = 9

Notes

Trivially, any number in the 1-9 range is narcissistic and any two-digit number is not.
Curious fact: Only 88 numbers are narcissistic.