1191
1191 is the year Richard I captured Acre on the Third Crusade.
- Odd
- Composite
Where 1191 fits
Why 1191 is special
He spent about six months of a ten-year reign in England and is nonetheless among the most recognised English kings, largely through later legend.
Factors & digit properties
- Divisors (4)
- 1, 3, 397, 1191
- Prime factorisation
- 3 × 397
- Digit sum
- 12
- Digital root
- 3
Representations
- Decimal
- 1191
- Binary
- 10010100111
- Octal
- 2247
- Hexadecimal
- 4a7
- Roman numeral
- MCXCI
- Scientific notation
- 1.191 × 10^3
Other mathematical patterns
- Deficient number
- Semiprime
Related numbers & connections
Richard I took Acre in 1191 on the Third Crusade, called after Saladin retook Jerusalem in 1187.
View 1187 →Other connections
- is associated with1187
why?
Strength 0.50, confidence "high".
History
Richard I spent roughly half a year of a ten-year reign in England, speaking little or no English. His prominence in English memory is almost entirely a construction of later storytelling.
DocumentedHistoryGeography: England and the LevantPeriod: 1191
Common questions
Is 1191 a prime number?
No, 1191 is not prime.
What are the factors of 1191?
The factors of 1191 are 1, 3, 397, 1191.
What is 1191 in Roman numerals?
1191 in Roman numerals is MCXCI.
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: 3 August 2026