```
class Solution(object):
def getFactors(self, n):
"""
:type n: int
:rtype: List[List[int]]
"""
if n==1:
return []
ret = []
def helper(n,index,path):
if n<index:
return
for i in range(index,int(math.sqrt(n))+1):
if n%i == 0:
ret.append(path+[i,n//i])
helper(n//i,i,path+[i])
helper(n,2,[])
return ret
```