Invalid syntax error

[sl33k]

I'm trying project euler problem 3 and I've hit the wall with this
error. What could be the problem here?

 l=[]
>>> num=600851475143
>>> i=1
>>> while i<=num:
...     if num%i==0:
...         l.append(i)
...     i+=1
... print max(l)
  File "<stdin>", line 5
    print max(l)
        ^
SyntaxError: invalid syntax