> why is 2^68 0% of the "numbers that need to be checked"? The vast majority of natural numbers are larger than 2^68. Only 2^68 of them are less than 2^68, but

> why is 2^68 0% of the "numbers that need to be checked"? The vast majority of natural numbers are larger than 2^68. Only 2^68 of them are less than 2^68, but infinitely many of them are greater.