1391
1391 is a year in the 14th century. Anti-Jewish riots spread across Castile and Aragon, producing mass conversions and the converso question (Iberia).
- Odd
- Composite
Where 1391 fits
Why 1391 is special
1391 has a profile because of what happened in it rather than because of any property of the number: anti-Jewish riots spread across Castile and Aragon, producing mass conversions and the converso question (Iberia).
1391 is part of
Factors & digit properties
- Divisors (4)
- 1, 13, 107, 1391
- Prime factorisation
- 13 × 107
- Digit sum
- 14
- Digital root
- 5
Representations
- Decimal
- 1391
- Scientific notation
- 1.391 × 10^3
Roman numerals
M C C C X C I
MCCCXCI uses the subtractive pair XC: ten before a hundred — a hundred minus ten.
Binary
1 0 1 0 1 1 0 1 1 1 1
1 × 1,024 + 0 × 512 + 1 × 256 + 0 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 1 × 2 + 1 × 1 = 1,391
Octal
2 5 5 7
2 × 512 + 5 × 64 + 5 × 8 + 7 × 1 = 1,391
Hexadecimal
5 6 f
5 × 256 + 6 × 16 + f × 1 = 1,391
Read as powers of two: 1,024 + 256 + 64 + 32 + 8 + 4 + 2 + 1 = 1,391.
In historical numeral systems
Egyptian
1 lotus, 3 coils of rope, 9 hobbles, 1 stroke
1 × 1,000 + 3 × 100 + 9 × 10 + 1 × 1 = 1,391. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
2 corner wedges + 3 vertical wedges (sixties place), 1 corner wedge + 1 vertical wedge (units place)
23 × 60 + 11 = 1391. 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
1391 is a year in the 14th century, in the 1390s.
Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
History
In 1391, anti-Jewish riots spread across Castile and Aragon, producing mass conversions and the converso question (Iberia).
DocumentedHistoryGeography: IberiaPeriod: 1391
Common questions
Is 1391 a prime number?
No, 1391 is not prime.
What are the factors of 1391?
The factors of 1391 are 1, 13, 107, 1391.
What is 1391 in Roman numerals?
1391 in Roman numerals is MCCCXCI. XC is subtractive: ten before a hundred — a hundred minus ten. Written additively it would be MCCCLXXXXI, 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