Unlike other prime tests on scratch, this does not only check your number against a list of preloaded primes. First, it tests against a list of calculated primes, if not found there, it will calculate to see if it's prime. If so, add to the prime list. The prime list, although very long, only started with 7 primes that I typed in. WARNING! A VERY LARGE NUMBER COULD LAG YOUR COMPUTER.
Now the test works for all values! Try 524287
