so that the calculator can automatically list the prime factors in a number, like a scientific calculator would

Please Add. in Converter Chart ---
Glass Size - Height X Width & Glass thickness = Glass Weight par. Sq. Ft. in Kg.

Sync calculations history between computers

How about making a savings calculator to see how much you can earn by making periodic investments at a given yield. This could be built into the loan expert page

improve number readability-.

Use user´s keyboard layout. I, for an instance, use "," for decimals while the calculator only accepts "." And I don´t have "." on my computer numeric pad

Select tablespoons to teaspoons. Press 1, then 3 teaspoons appears (correct) and then press . (period) 0 and it changes to 0.3 teaspoons - incorrect!

Make it so if you get a repeating decimal such as pi as an answer, you can see more digits.

Say it displays 9000m instead of m9000

Let users change colors on the calculator, post stickers around it and keep it as it's original feature,

it's used to calculate financial ratios

like changing radians to degrees or degrees to degrees minutes seconds

Examples:
Volume - bbl to m3 to gal(us) etc....
Pressures - you have pascals, but could you add kPa and MPa? I know its just simple divisions, but it's just handy to have.
Forces - The same as pressures, daN
Flow Rates - gal(us)/day, hour, minute, and second. cubic foot, liter, cubic meter, barrels (bbl) etc.
Thanks.

The current gray gradient background is pretty chic, but when shifting continuously (like, when doing homework) between the calculator and another page with the traditional white b/g-black text format, it hurts the eyes. Takes a few seconds to re-focus the vision.

My easier-to-read version would be a silver/metallic (a light shade) background and the rest could probably just stay.