One approach to bible study is to look for prior uses of the subject material.
The number 666 was the number of silver talons that Solomon taxed his people after he turned from God.
This represented a huge burden on the people of Israel, and this level of taxation practically made them slaves.
So 666 means using in this context the Antichrist will raise taxes to unbearable levels and enslave his people.
You might want to cross-post this on ‘the meaning of 666’ thread.