Scientific and Normal notation
In settings you can change between Scientific and Normal notation.
Normal Notation uses abbreviations for denominations for example 9 million or 9,000,000 is 9 M.
Scientific Notation is written where the number after e is the number of zeros that follow. For example 9e6 is 9,000,000 or 9 million. The Game only uses Multiplies of 3 in Scientific Notation so it matches Normal Notation where you switch between them.
An example is pictured below with the 4th and 5th Achievements for A Motherlode of Cash, outlined in red below.
Normal top and Scientific bottom: