3,840
3,840 is the pixel width of 4K UHD, the resolution most televisions and monitors sold as 4K actually use.
- Even
- Composite
Where 3,840 fits
Why 3,840 is special
It is exactly twice 1,920, which is what makes it a clean upgrade from 1080p — every old pixel becomes four new ones with no resampling. The cinema standard called 4K is 4,096 wide instead, so the consumer format is named after a number it does not have.
Factors & digit properties
- Divisors (36)
- 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 48, 60, 64, 80, 96, 120, 128, 160, 192, 240, 256, 320, 384, 480, 640, 768, 960, 1280, 1920, 3840
- Prime factorisation
- 2^8 × 3 × 5
- Digit sum
- 15
- Digital root
- 6
Representations
- Decimal
- 3840
- Scientific notation
- 3.840 × 10^3
Roman numerals
M M M D C C C X L
MMMDCCCXL uses the subtractive pair XL: ten before fifty — fifty minus ten.
Binary
1 1 1 1 0 0 0 0 0 0 0 0
1 × 2,048 + 1 × 1,024 + 1 × 512 + 1 × 256 + 0 × 128 + 0 × 64 + 0 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 0 × 2 + 0 × 1 = 3,840
Octal
7 4 0 0
7 × 512 + 4 × 64 + 0 × 8 + 0 × 1 = 3,840
Hexadecimal
f 0 0
f × 256 + 0 × 16 + 0 × 1 = 3,840
Read as powers of two: 2,048 + 1,024 + 512 + 256 = 3,840.
In historical numeral systems
Egyptian
3 lotuses, 8 coils of rope, 4 hobbles
3 × 1,000 + 8 × 100 + 4 × 10 = 3,840. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Systems that simply cannot reach this value are left out. Where a script needs a font most readers do not have, the reading is given instead of the glyphs — see number systems for each system in full.
Other mathematical patterns
- Abundant number
- Harshad (Niven) number
Technology & computing
The pixel width of 4K UHD is 3840 (worldwide, ITU-R BT.2020). Exactly twice 1,920, so every 1080p pixel becomes four with no resampling. The cinema standard called 4K is 4,096 wide, so the consumer format is named after a number it does not have.
DocumentedTechnology & computingGeography: worldwide, ITU-R BT.2020
Common questions
Is 3,840 a prime number?
No, 3,840 is not prime.
What are the factors of 3,840?
The factors of 3,840 are 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 48, 60, 64, 80, 96, 120, 128, 160, 192, 240, 256, 320, 384, 480, 640, 768, 960, 1280, 1920, 3840.
What is 3,840 in Roman numerals?
3,840 in Roman numerals is MMMDCCCXL. XL is subtractive: ten before fifty — fifty minus ten. Written additively it would be MMMDCCCXXXX, which Roman inscriptions used freely — the strict subtractive form is a later convention.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 15 July 2026