What's your idea of a perfect number?
Mine is:

default decimal, prefix for binary, octal, hex

Integers in natural notation with strictly positive exponent

All bases allow natural notation, where the exponent is always a decimal number and represents the power of the base (0b101e3 = 0b101000)

Floats in all bases allow a combination of natural notation and dot notation

Underscores allowed anywhere except the beginning and end for easier reading