So, the greatest common divisor of 36 and 90 will be the product of the factors that they have in common.

36 90 大公约是它们公约乘积。

This question of counting the number of lattice points a distance sqrt(N) away from the origin involves adding up the value of this simple function over all divisors of N. Now, remember why we're doing all of this.

计算距离原点sqrt(N)远格点量这问题涉及将这简单函在N所有除上求。 现在，记得我们为什么要这样做。

We'll begin by finding the greatest common divisor of 36 and 90.

我们先求 36 90 大公约。

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.

因子多有很多约，素只有两约， 你可能会认为需要完全掌握素分布才能从这当中得到有用信息。