8091
Annapurna is 8,091 metres high and has the highest fatality rate of the eight-thousanders.
- Odd
- Composite
Where 8091 fits
Why 8091 is special
It was also the first eight-thousander ever climbed, in 1950, three years before Everest. Being first and being deadliest are both true of it.
Factors & digit properties
- Divisors (12)
- 1, 3, 9, 29, 31, 87, 93, 261, 279, 899, 2697, 8091
- Prime factorisation
- 3^2 × 29 × 31
- Digit sum
- 18
- Digital root
- 9
Representations
- Decimal
- 8091
- Scientific notation
- 8.091 × 10^3
Roman numerals
Roman numerals as modelled here goes up to 3,999.
Binary
1 1 1 1 1 1 0 0 1 1 0 1 1
1 × 4,096 + 1 × 2,048 + 1 × 1,024 + 1 × 512 + 1 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 1 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 8,091
Octal
1 7 6 3 3
1 × 4,096 + 7 × 512 + 6 × 64 + 3 × 8 + 3 × 1 = 8,091
Hexadecimal
1 f 9 b
1 × 4,096 + f × 256 + 9 × 16 + b × 1 = 8,091
Read as powers of two: 4,096 + 2,048 + 1,024 + 512 + 256 + 128 + 16 + 8 + 2 + 1 = 8,091.
In historical numeral systems
Egyptian
8 lotuses, 9 hobbles, 1 stroke
8 × 1,000 + 9 × 10 + 1 × 1 = 8,091. 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
Related numbers & connections
Cho Oyu is the usual first eight-thousander and Annapurna has the highest fatality rate of the fourteen. Height is a poor predictor of danger.
View 8188 →Other connections
- contrasts with8188
why?
Strength 0.50, confidence "high".
Geography
Annapurna was the first eight-thousander summited, in 1950, and carries the highest death-to-summit ratio of the fourteen. Neither fact is a consequence of the other.
DocumentedGeographyGeography: Nepal
Common questions
Is 8091 a prime number?
No, 8091 is not prime.
What are the factors of 8091?
The factors of 8091 are 1, 3, 9, 29, 31, 87, 93, 261, 279, 899, 2697, 8091.
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