1243
1243 is a year in the 13th century. Montsegur was besieged, and its fall the next year effectively ended Cathar resistance (France).
- Odd
- Composite
Where 1243 fits
Why 1243 is special
1243 has a profile because of what happened in it rather than because of any property of the number: Montsegur was besieged, and its fall the next year effectively ended Cathar resistance (France).
1243 is part of
Factors & digit properties
- Divisors (4)
- 1, 11, 113, 1243
- Prime factorisation
- 11 × 113
- Digit sum
- 10
- Digital root
- 1
Representations
- Decimal
- 1243
- Scientific notation
- 1.243 × 10^3
Roman numerals
M C C X L I I I
MCCXLIII uses the subtractive pair XL: ten before fifty — fifty minus ten.
Binary
1 0 0 1 1 0 1 1 0 1 1
1 × 1,024 + 0 × 512 + 0 × 256 + 1 × 128 + 1 × 64 + 0 × 32 + 1 × 16 + 1 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 1,243
Octal
2 3 3 3
2 × 512 + 3 × 64 + 3 × 8 + 3 × 1 = 1,243
Hexadecimal
4 d b
4 × 256 + d × 16 + b × 1 = 1,243
Read as powers of two: 1,024 + 128 + 64 + 16 + 8 + 2 + 1 = 1,243.
In historical numeral systems
Egyptian
1 lotus, 2 coils of rope, 4 hobbles, 3 strokes
1 × 1,000 + 2 × 100 + 4 × 10 + 3 × 1 = 1,243. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
2 corner wedges (sixties place), 4 corner wedges + 3 vertical wedges (units place)
20 × 60 + 43 = 1243. 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
- Semiprime
Related numbers & connections
1243 is a year in the 13th century, in the 1240s.
Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
History
In 1243, Montsegur was besieged, and its fall the next year effectively ended Cathar resistance (France).
DocumentedHistoryGeography: FrancePeriod: 1243
Common questions
Is 1243 a prime number?
No, 1243 is not prime.
What are the factors of 1243?
The factors of 1243 are 1, 11, 113, 1243.
What is 1243 in Roman numerals?
1243 in Roman numerals is MCCXLIII. XL is subtractive: ten before fifty — fifty minus ten. Written additively it would be MCCXXXXIII, 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