Problem #41 Difficulty: 5%

Pandigital Prime

Solution Language: Java
View Solution View on Project Euler

Problem Statement

We shall say that an n-digit number is pandigital if it makes use of all the digits 1 to n exactly once. For example, 2143 is a 4-digit pandigital and is also prime.

What is the largest n-digit pandigital prime that exists?

Approach

The solution involves:

  1. Recognizing that 9-digit and 8-digit pandigitals are divisible by 3 (sum of digits)
  2. Generating all 7-digit pandigitals in descending order
  3. Checking each for primality
  4. Returning the first (largest) prime found