Understanding & converting color codes: RGB v Hex v ARGB v RGBA…

Hello,

Regarding color codes and converting between them, are ARGB & RGBA identical except for the alpha transparency value position? Are they interchangeable?

Also, what is the "0x" prefix which is so commonly included?

Example (from the 2nd link included below):

"ARGB integer value (0xAARRGGBB) or HTML color name ("Red")."

I understand RGB & Hex and how to convert back and forth but I've not used the alpha parameter previously. I've read that it's a hex value which defines transparency but that's about it.

Specifically, I'm trying to build a GUI with multiple colors of buttons using AutoHotkey (AHK) and an AHK utility found here:

http://ahkscript.org/boards/viewtopic.php?f=6&t=1103
https://github.com/AHK-just-me/Class_ImageButton

Thanks