素数分解：、在许多情况下，知道一个数是素数还不够，还需要知道它的约数。每个大于1的正整数都能表示为素数的乘积。这个因数分解是唯一的，被称为素数分解（prime factorization）。例如60可以分解为2x2x3x5，其中每个约数都是素数。注意，同一个素数在因数分解中可以出现多次。

-Prime decomposition: in many cases, know that a number is prime is not enough, it also needs to know about the number. Every positive integer greater than 1 can be expressed as the product of prime numbers. This factorization is unique, known as prime decomposition (prime factorization). For example, 60 can be decomposed into 2x2x3x5, which are each about the number of primes. Note that, in the same prime factorization can appear multiple times.