255
255 is the maximum value an 8-bit number can hold (2⁸ − 1), which is why it's the highest value for a single RGB colour channel and appears throughout digital colour and computing.
- Odd
- Composite
Where 255 fits
Why 255 is special
255's significance is entirely structural, not mathematical: an 8-bit binary number has 256 possible values (0 through 255), so 255 is simply the largest one representable. That single fact explains why RGB colour channels (red, green, blue) each max out at 255, why the two-digit hexadecimal pair "FF" equals 255, and why it shows up as a maximum or overflow boundary throughout computing — not because 255 has any interesting mathematical property in its own right.
255 in Numbers Around Us
255 is part of
Factors & digit properties
- Divisors (8)
- 1, 3, 5, 15, 17, 51, 85, 255
- Prime factorisation
- 3 × 5 × 17
- Digit sum
- 12
- Digital root
- 3
Representations
- Decimal
- 255
- Binary
- 11111111
- Octal
- 377
- Hexadecimal
- ff
- Roman numeral
- CCLV
- Scientific notation
- 2.550 × 10^2
Other mathematical patterns
- Deficient number
Related numbers & connections
255 is the maximum value for a single RGB colour channel under standard 8-bit colour.
Numbers Around Us
- appears inRGB colour model
why?
Strength 0.50, confidence "high".
- appears inHexadecimal colour notation
why?
Strength 0.50, confidence "high".
Technology & computing
255 is the maximum value an 8-bit number can hold (2⁸ − 1), which is why it's the standard maximum for a single RGB colour channel and the value represented by the hexadecimal pair "FF".
DocumentedTechnology & computing255 is the maximum value an 8-bit number can hold (2⁸ − 1), which is why it's the standard maximum for a single RGB colour channel and the value represented by the hexadecimal pair "FF".
DocumentedTechnology & computing
Common questions
Is 255 a prime number?
No, 255 is not prime.
What are the factors of 255?
The factors of 255 are 1, 3, 5, 15, 17, 51, 85, 255.
What is 255 in Roman numerals?
255 in Roman numerals is CCLV.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026