"This calls for wisdom: let anyone with understanding calculate the number of the beast, for it is the number of a person. Its number is six hundred sixty-six."
There are plenty of theories about this number and the gematria involved in trying to figure out whom it represents.
Ellicott's commentary at Biblehub.com notes that the number has been translated as 616 as well as 666, and he takes a more symbolic view of the number as symbolizing the lack of perfection of mankind. Perfection, being symbolized by the number seven, is only attainable through God. Benson's commentary at the same link has some interesting theories on gematria at the very end of his writing.
In the blog on these verses at gotquestions.org, the writer reassures the reader that when this mark is given it will be completely clear to Christians that this is the anti-Christ, and that people take this mark as a seal of worship of the devil over Christ. The writer states confidently that people will know when they take the mark just how the number 666 is tied to this person.
A Prayer for Salvation from Christ:
Lord
Jesus, I confess my sins and ask for your forgiveness. Please come into
my heart as my Lord and Savior. Take complete control of my life and
help me to walk in Your footsteps daily by the power of the Holy Spirit.
Thank you Lord for saving me and for answering my prayer.
A more detailed step by step process:
https://www.wikihow.com/Accept-Jesus-Into-Your-Life
