It seems to me that
千 is exceptional in having it prefixed with
百, they work together with
千to describe the numbers from 1 to 9999, so they compete with one another, or are complimentary. There is no combination like:
一一, 一十, 一百, 十十, 十百 百百
京, etc., they are multiplied by a number from 1 to 9999, expressed by the prefix using
千, so when that prefix turns out to be 1, 10, 100, 1000, then they are combined, and there are combinations like:
一万, 十万, 百万, 千万, 一億, 十億, 百億, 千億, etc.
and there is no combination among themselves such as
万万, 万億, 億億, 万兆, 億兆, 兆兆, etc.
千 is exceptional in that it is prefixed by
一 just when itself is prefixed to the characters
千 prefixed with
一 in this case? Why is it not like the following?