Lua函数参数被视为字符串？

我试图在 Lua 中编写一个因数分解程序，除了其中一行代码以外，一切都有效。以下是代码：

function factor(a)
 print("factoring: " .. a)
 print()
 totali = 0
 totaldiv = 0
 for i = 1, a do
  if (a%i == 0) then
   if (i<a) then
    totaldiv = totaldiv + 1
   end
   print(i)
   i = i + 1
   totali = totali + 1
  else
   i = i + 1
  end
 end
 if totali == 2 then
  print("That is a prime number!")
 elseif totaldiv == a then
  print("That is a perfect number!")
 end
end
io.write("Enter a number to factor: ")
some = io.read()
factor(some)
io.read()

我发现有问题的行是 if (i<a) then。 我做错了什么？ 谢谢！