Actually, the 666 comes from an interpretation of the "Book of Revelation".
Wrong again. There are a lot of hypotheses as to the origin of 666 including that they represent letters (www), not numbers. And the reference in revelation was shown to be some other number, not 666. But it was Hollywood that popularized 666 as the "mark of the beast".
Otherwise, I agree that it is a good frequency and is include in one of my new models of zapper that is currently on test. However, I do not rely entirely on that frequency as my data analysis shows that there are things that it misses.
As an example, 666 seems to have little effect on Basal Cell but frequencies close to the following work extremely well. 2116, 2280,
Also, 666 does not appear to help with non-Hodgkin's Lymphoma but 2008, 2004, 2012, 2116, 2128 ...
Gotta love that 7.83 or some like the 15.66 but somehow round it down to 15.0 ( Croft ).
Clearly you are doing something wrong because the 666hz frequency works for those cancers as well. Again, what Rife was doing really had nothing to do with vibrating cells apart. Once you figure out the why this and his other two frequencies work then you will understand why it also works for these other cancers. Ironically you actually got part of the answer there in your post, but you still have a long way to go to figure it out.