1291
1291 is the traditional founding date of the Swiss Confederation.
- Odd
- Prime
Where 1291 fits
Why 1291 is special
Three valley communities swore mutual defence, and the charter survives. Switzerland's national day marks it, though the modern federal state dates from 1848.
1291 is part of
Factors & digit properties
- Divisors (2)
- 1, 1291
- Prime factorisation
- 1291
- Digit sum
- 13
- Digital root
- 4
Representations
- Decimal
- 1291
- Scientific notation
- 1.291 × 10^3
Roman numerals
M C C X C I
MCCXCI uses the subtractive pair XC: ten before a hundred — a hundred minus ten.
Binary
1 0 1 0 0 0 0 1 0 1 1
1 × 1,024 + 0 × 512 + 1 × 256 + 0 × 128 + 0 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 1,291
Octal
2 4 1 3
2 × 512 + 4 × 64 + 1 × 8 + 3 × 1 = 1,291
Hexadecimal
5 0 b
5 × 256 + 0 × 16 + b × 1 = 1,291
Read as powers of two: 1,024 + 256 + 8 + 2 + 1 = 1,291.
In historical numeral systems
Egyptian
1 lotus, 2 coils of rope, 9 hobbles, 1 stroke
1 × 1,000 + 2 × 100 + 9 × 10 + 1 × 1 = 1,291. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
2 corner wedges + 1 vertical wedge (sixties place), 3 corner wedges + 1 vertical wedge (units place)
21 × 60 + 31 = 1291. 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
- Deficient number
- Lucky number (mathematical sieve)
- Twin prime
Related numbers & connections
1291 is a year in the 13th century, in the 1290s.
The Swiss Confederation is dated from a 1291 pact between three valley communities, and the modern federal state from 1848 — five and a half centuries apart.
View 1848 →Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
Other connections
- is associated with1848
why?
Strength 0.50, confidence "high".
History
In 1291, Acre fell and the crusader states on the mainland ended (Levant).
DocumentedHistoryGeography: LevantPeriod: 1291In 1291, the Federal Charter between three forest cantons is taken as the founding of the Swiss Confederation (Switzerland).
DocumentedHistoryGeography: SwitzerlandPeriod: 1291The 1291 pact between three Alpine communities is Switzerland's founding document and its national day. The federal state as it exists now was created in 1848, five and a half centuries later.
DocumentedHistoryGeography: SwitzerlandPeriod: 1291
Common questions
Is 1291 a prime number?
Yes, 1291 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 1291?
The factors of 1291 are 1, 1291.
What is 1291 in Roman numerals?
1291 in Roman numerals is MCCXCI. XC is subtractive: ten before a hundred — a hundred minus ten. Written additively it would be MCCLXXXXI, 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: 3 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026