Numerology has been defined as the fascinating play of numbers or the Astrology of Numbers
One represents the Soul of the Cosmic Man, the Sun. 0 represents Universal Nature. If you add a lot of zeroes to the One on the right side and divide it by 7, you will get 142857 as the remainder
and if you add all the digits, you get Nine
If you add 1+4+2+8+5+7, you get 9 !
Now you can imagine why 1, 9 and 7 are considered to be mystic numbers !