public void largestPrimeFinder(long num) {
		System.out.println("Starting...");
		//goal number is 600851475143
		long largestPrime = 0;
		
		for (long i = num - 1; i > 1l; i--) {
			if (num % i == 0) {   //First find a factor of the number
				if (isPrime(i)) {    //Then determine if it is prime; if so, you've found the largest prime
					largestPrime = i;
					break;
				}
			}
		}
		System.out.println("Largest prime: " + largestPrime);
	}