I am wondering which numeral system different programmers are using, or would use if their language has support for them. As an example, in C++ we can use:

• Octal by prefixing with 0 (e.g. 0377)
• Decimal by default (e.g. 255)
• Hexadecimal by prefixing with 0x (e.g. 0xff)

When working with bitmask, I am using hexadecimal but would sometimes want to be able to express binary numbers directly. I know some programming language support it with 0b syntax (e.g. 0b11111111).

Is there any other numeric system useful in some computer science domain (e.g. cryptography, codecs, 3D graphics, etc)?