When I first heard about Order 66, the number intrigued me. Why would George Lucas choose the number 66 to represent this genocidal order? Let’s take a look a possible explanation.
In Biblical numerology, the number 6 can be used to represent spiritual imperfection in man, the devil, or the spirit of the devil in mankind. It is an imperfect number. Hence, the reason 666 is considered to be the Number of the Beast (well known to Iron Maiden fans).
The number 666 (originally 616 in early texts) in Biblical terms is the “Unholy Trinity” or also the perfection of imperfection, just as 777 represents the “Holy Trinity” or actual perfection and holiness.
The number 11 in Biblical terms represents disorder, disorganization, imperfection, and disintegration. So 6 X 11 (imperfection X destruction) equals Order 66. The evil in man (The Sith/Darth Sidious) combined with destruction (of the Republic) is exemplified in this number.
This same formula can be used to represent the 66 books of the King James Bible but without as serious an end result. The spirit of Satan (6) X destruction (11) = Satan destroyed by God’s Word (66).
Lucas has been known to reference all kinds of historical, spiritual and religious imagery throughout his career. It would not surprise me to find out there was something behind the number 66.
On the other hand, it could all just be a freaky coincidence and the number 66 could refer to the year of a car or something.