Largest prime factor

largestprimefactor.java

// Largest prime factor of number
public long primeFactor(long number) {
	long largestFactor=0;
	for (long n=2; n<=(int)Math.sqrt(number); n++) {
		// n is a factor of number
		if(number%n == 0) {
			// Is n prime?
			boolean isPrime=true;
			for (long i=2; i<=(int)Math.sqrt(n); i++) {
				if(n%i == 0) { // i is a factor of n
					isPrime=false;
					break;
				}
			}
			
			if(isPrime) {
				if (n>largestFactor)
					largestFactor=n;
				// System.out.println(n); // Print the prime factors
			}
		}
		
		// Every thousand, let the user know we're still working
		if(n%1e3==0) System.out.print(".");
	}
	
	System.out.println("");
	return largestFactor;
}