In the Old Testament, 666 was the number of gold talents that king Solomon received from the nations he had subjugated. (1Kings 10:14). His power was symbolized by "666".
In Revelation 13 we read "Let the person who has insight calculate the number of the beast, for it is the number of a man. That number is 666."
It's not saying "sit down with a pen and a notebook and try to convert 666 into alphabets".
It's saying figure out "Find out who used 666 in the past and you'll know what the name is and what he will be like".
So if 666 represents the name of the anti-Christ, it's saying the anti-Christ's name will be Solomon or some other variant of it. It's saying that, like King Solomon, the antichrist's power will also be symbolized by 666.
The anti-Christ is an imposter who appears in place of the real Christ, will sit on Solomon's throne. He will be an EVIL VERSION of king Solomon.