1279
1279 is the year the Song dynasty fell to the Mongols.
- Odd
- Prime
Where 1279 fits
Why 1279 is special
China was ruled by a foreign dynasty for the first time in its entirety. Song China had had paper money, gunpowder weapons and printing, and much of that technical lead was transmitted westward under Mongol rule.
1279 is part of
Factors & digit properties
- Divisors (2)
- 1, 1279
- Prime factorisation
- 1279
- Digit sum
- 19
- Digital root
- 1
Representations
- Decimal
- 1279
- Scientific notation
- 1.279 × 10^3
Roman numerals
M C C L X X I X
MCCLXXIX uses the subtractive pair IX: one before ten — ten minus one.
Binary
1 0 0 1 1 1 1 1 1 1 1
1 × 1,024 + 0 × 512 + 0 × 256 + 1 × 128 + 1 × 64 + 1 × 32 + 1 × 16 + 1 × 8 + 1 × 4 + 1 × 2 + 1 × 1 = 1,279
Octal
2 3 7 7
2 × 512 + 3 × 64 + 7 × 8 + 7 × 1 = 1,279
Hexadecimal
4 f f
4 × 256 + f × 16 + f × 1 = 1,279
Read as powers of two: 1,024 + 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 1,279.
In historical numeral systems
Egyptian
1 lotus, 2 coils of rope, 7 hobbles, 9 strokes
1 × 1,000 + 2 × 100 + 7 × 10 + 9 × 1 = 1,279. 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), 1 corner wedge + 9 vertical wedges (units place)
21 × 60 + 19 = 1279. 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
- Twin prime
Related numbers & connections
1279 is a year in the 13th century, in the 1270s.
The Song fell to the Mongols in 1279 and the Ming expelled them in 1368, restoring native rule after eighty-nine years.
View 1368 →History
In 1279, the Song dynasty ended and the Mongol Yuan ruled all China (China).
DocumentedHistoryGeography: ChinaPeriod: 1279Song China had movable type, paper currency and gunpowder before its conquest in 1279. Mongol control of the overland routes is a substantial part of how those technologies reached Europe.
DocumentedHistoryGeography: ChinaPeriod: 1279
Common questions
Is 1279 a prime number?
Yes, 1279 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 1279?
The factors of 1279 are 1, 1279.
What is 1279 in Roman numerals?
1279 in Roman numerals is MCCLXXIX. IX is subtractive: one before ten — ten minus one. Written additively it would be MCCLXXVIIII, 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