Describe the relationship between the values of the digits in the number 9,999,999

Because all the digits are the same, each digit is worth 10x the one to its right and 1/10 of the one to its left.
This is because we count in base 10. This is also why we can expand this number to become
9*10^6+ 9*10^5+ 9*10^4+ 9*10^3+ 9*10^2+ 9*10^1 +9*10^0.

These are the multiples of 15 but what you are probably asking or what are the factors of 15