6543
NGC 6543 is the Cat's Eye Nebula.
- Odd
- Composite
Where 6543 fits
Why 6543 is special
It was the first planetary nebula whose spectrum was examined, which showed it was glowing gas rather than a cluster of unresolved stars.
6543 is part of
Factors & digit properties
- Divisors (6)
- 1, 3, 9, 727, 2181, 6543
- Prime factorisation
- 3^2 × 727
- Digit sum
- 18
- Digital root
- 9
Representations
- Decimal
- 6543
- Scientific notation
- 6.543 × 10^3
Roman numerals
Roman numerals as modelled here goes up to 3,999.
Binary
1 1 0 0 1 1 0 0 0 1 1 1 1
1 × 4,096 + 1 × 2,048 + 0 × 1,024 + 0 × 512 + 1 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 1 × 2 + 1 × 1 = 6,543
Octal
1 4 6 1 7
1 × 4,096 + 4 × 512 + 6 × 64 + 1 × 8 + 7 × 1 = 6,543
Hexadecimal
1 9 8 f
1 × 4,096 + 9 × 256 + 8 × 16 + f × 1 = 6,543
Read as powers of two: 4,096 + 2,048 + 256 + 128 + 8 + 4 + 2 + 1 = 6,543.
In historical numeral systems
Egyptian
6 lotuses, 5 coils of rope, 4 hobbles, 3 strokes
6 × 1,000 + 5 × 100 + 4 × 10 + 3 × 1 = 6,543. 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
- Deficient number
- Happy number
Related numbers & connections
The Helix is close enough to appear large and faint where the Cat's Eye appears small and bright.
View 7293 →Science
William Huggins observed NGC 6543 spectroscopically in 1864 and found emission lines rather than a continuous spectrum, establishing that some nebulae are gaseous.
DocumentedSciencePeriod: 1786–
Common questions
Is 6543 a prime number?
No, 6543 is not prime.
What are the factors of 6543?
The factors of 6543 are 1, 3, 9, 727, 2181, 6543.
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