4.Numbers with lots of factors have lots of divisors, primes only have two divisors, and you might think that you'd need perfect knowledge of the distribution of primes to get anything useful out of this.
有很多因数的数字有很多约数,素数只有两个约数, 你可能认为你需要完全了解素数的分布才能从中得到任何有用的东西。机翻