Xml Satan is a belief based entity. I don't think it possible to physically defeat him. Though if this is something you are serious about, you could look into christianity. If I remember correctly, living a pious life as free of sin as possible is how they believe their fight against him can be won. Though do not take my word as fact on this. Have not attended church in over ten years.
While satin can be bothersome to sew [what with it sliding around when you try to pin it] I think you wish to defeat Satan aka the devil.
Satan is a belief, and I don't believe in him. So I ask you why you wish to defeat him? Unless he's harassing you you might consider focusing on positive things, 'the light of the Lord' can defeat Satan, or so people say. Theoretically if you're a good person you probably won't be bothered by him. But that's just a suggestion, I don't believe in an all good deity and all evil deity doing battle, so there might be other things to do.
JUst one small point, 666 is not the number of Satan, it is the number of the beast of revelations, which is the number of a man (or all men depending on how one interprets such things).
666 is actually the enumeration of the Greek phrase To Mega Therion, or "The Great Beast".
As for defeating Satan, simply don't believe in him and he no longer exists in an anthropomorphic form- the same as any deity.
@hadit, the beast you are taking about his number is sometimes termed as 666,but in true sense his number is 999 and 666 represents the Sun, Satan's has many termed numbers like 7,11, 40 etc...
I believe that, according to Christian belief, you cannot destroy Satan. Even the Christian God feels a need for Satan to be present so that Christians can learn to choose good over evil. But the Bible also says that each person can defeat Satan within their own lives by choosing to do only those things that are righteous. When Jesus went into the desert and struggled with Satan he could not destroy him, but he could choose not to let Satan have power in his life.
Personally I don't believe in the existence of an actual being known as Satan. I think that the whole idea of Satan and Hell is simply a way to make people afraid of doing something for which they'll be punished. Doing right because if you don't you'll be punished isn't, to me, as good as doing right because it is the proper thing to do.
