求一个整数的约数
方法一：
num = int(input())
num1 = num
t = []
for i in range(2, num+1):
while num % i == 0:
t.append(str(i))
num /= i
print(t)
方法二：
num = int(input())
num1 = num
t = []
def func(n):
for i in range(2, n+1):
if n % i == 0:
t.append(str(i))
return n // i
return str(n)
while num != 1:
num = func(num)
print(t)
