How to change the scaling of a TGraph?

Is there a way to change the scaling of a particular axis without modifying the dataset? I am working with values with magnitude of 10^18 in x axis and 10^-15 on the y axis. ROOT keeps scaling the x axis for x10^15, which is not what I want, I want it to scale for 10^18 . How can I achieve this?

It can only be rescaled for the appropiate magnitude if the limits were set for more than x10^2 for the boundary wanted. Setting the boundaries

data->GetXaxis()->SetLimits(0, 0.12e20);

like this gave me what I want, showing the x axis in the scope of x10^18 for some reason…