24-bit

1 4 8 12 16 18 24 26 31 32 36 48 60 64 128 256 512

16 32 64

×½ ×1 ×2 ×4 ×8

32 64 128

In computer architecture, 24-bit integers, memory addresses, or other data units are those that are at most 24 bits (3 octets) wide. Also, 24-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size.

Notable 24-bit machines include the CDC 924 - a 24-bit version of the CDC 1604, CDC lower 3000 series, SDS 930 and SDS 940, the ICT 1900 series, and the Datacraft minicomputers/Harris H series.

The IBM System/360, announced in 1964, was a popular computer system with 24-bit addressing and 32-bit general registers and arithmetic. The early 1980s saw the first popular personal computers, including the IBM PC/AT with an Intel 80286 processor using 24-bit addressing and 16-bit general registers and arithmetic, and the Apple Macintosh 128K with a Motorola 68000 processor featuring 24-bit addressing and 32-bit registers.

The eZ80 is a microprocessor and microcontroller family, with 24-bit registers and therefore 24-bit linear addressing, that is binary compatible with the 8/16-bit Z80.

...
Wikipedia