formatting numbers in plots

[David L Lorenz <lorenz@usgs.gov>]

I poked around a little in the documentation
and I can't find a hint about how to find out what controls the formatting
of large numbers in plots. In particular these are the diagnostic plots
from a linear regression. 

The range of the response variable is
from 0 to about 1,000,000
For the response vs fit plot, I get
x-axis and y-axis labels formatted like 200000, 400000, and so forth. Another
user gets them formatted like 2*10^5, 4*10^5 and so forth. 

What is controlling the formatting of
the labels? Thanks.
Dave