as you can see in the attached image i need to change only the size of the numbers not the title or the colorbar how can i do this? thank you
Use the 'FontSize' property of the current axes:
If you search for 'tick labels' or something similar, in the file exchange there are numerous options that replace the tick labels locked into the axes font size with text objects that can be manipulated independently.
I can't vouch for any particular one as I have never used any of them though.