Numerology is basically about putting meaning behind numbers. You can tell a persons personality by their birth numbers, and the path they will take in life. It is not perfect by any means, and rarely gives a complete story of someone. It has other uses as well but that is all I ever studied up on it lol.
Have you ever used numerology software? There are a few online that I've found quite accurate.
I like to combine numerology readings with different zodiacs, and a Myers-Briggs personality test. The results can be very comprehensive and can shed light onto numerous aspects of ones' life. They are a great tool for personal development and they pave the way for spiritual growth.
Most people who have little or no knowledge of the occult and esoteric claim that numerology is only a hoax, or call it "the work of the Devil". Modern scientists who promote materialism claim that it's a pseudoscience, even though Pythagoras is known to have used it.
To answer your question, it's not a divination process per se. It's considered to be a mystical science. It's based on certain mathematical patterns and can become quite complex depending on the knowledge you posses about it.