1891
1891 is the year basketball was invented.
- Odd
- Composite
Where 1891 fits
Why 1891 is special
James Naismith wrote thirteen rules to occupy students indoors during a New England winter. Peach baskets kept the ball, so someone had to retrieve it after every score.
Same number, different meanings
How 1891 is understood across different contexts — never implying one meaning because of another.
- Mathematics
James Naismith wrote thirteen rules to occupy students indoors during a New England winter. Peach baskets kept the ball, so someone had to retrieve it after every score.
- Technology & computing
In 1891, basketball was invented at Springfield, Massachusetts, using peach baskets nailed to a balcony (United States).
- Sport
Naismith invented basketball in December 1891 with thirteen written rules and two peach baskets. The bottoms were not removed for several years, so play stopped after every point.
1891 is part of
Factors & digit properties
- Divisors (4)
- 1, 31, 61, 1891
- Prime factorisation
- 31 × 61
- Digit sum
- 19
- Digital root
- 1
Representations
- Decimal
- 1891
- Scientific notation
- 1.891 × 10^3
Roman numerals
M D C C C X C I
MDCCCXCI uses the subtractive pair XC: ten before a hundred — a hundred minus ten.
Binary
1 1 1 0 1 1 0 0 0 1 1
1 × 1,024 + 1 × 512 + 1 × 256 + 0 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 1,891
Octal
3 5 4 3
3 × 512 + 5 × 64 + 4 × 8 + 3 × 1 = 1,891
Hexadecimal
7 6 3
7 × 256 + 6 × 16 + 3 × 1 = 1,891
Read as powers of two: 1,024 + 512 + 256 + 64 + 32 + 2 + 1 = 1,891.
In historical numeral systems
Egyptian
1 lotus, 8 coils of rope, 9 hobbles, 1 stroke
1 × 1,000 + 8 × 100 + 9 × 10 + 1 × 1 = 1,891. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges + 1 vertical wedge (sixties place), 3 corner wedges + 1 vertical wedge (units place)
31 × 60 + 31 = 1891. Places are separated by a space on the tablet, with the higher place written first.
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
- Triangular number
- Deficient number
- Hexagonal number
- Semiprime
Related numbers & connections
1891 is a year in the 19th century, in the 1890s.
Basketball was invented in December 1891 and its thirteen rules published in 1892 — one of very few major sports with a known inventor, date and original rulebook.
View 1892 →Technology & computing
In 1891, basketball was invented at Springfield, Massachusetts, using peach baskets nailed to a balcony (United States).
DocumentedTechnology & computingGeography: United StatesPeriod: 1891
Sport
Naismith invented basketball in December 1891 with thirteen written rules and two peach baskets. The bottoms were not removed for several years, so play stopped after every point.
DocumentedSportGeography: Massachusetts, United StatesPeriod: 1891
Common questions
Is 1891 a prime number?
No, 1891 is not prime.
What are the factors of 1891?
The factors of 1891 are 1, 31, 61, 1891.
What is 1891 in Roman numerals?
1891 in Roman numerals is MDCCCXCI. XC is subtractive: ten before a hundred — a hundred minus ten. Written additively it would be MDCCCLXXXXI, 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: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026