1644
1644 is the year the Ming dynasty fell.
- Even
- Composite
Where 1644 fits
Why 1644 is special
Beijing was taken by rebels and then by the Manchus, who founded the Qing dynasty and ruled until 1912. A rebellion succeeded and its leader lost the resulting empire within weeks.
Same number, different meanings
How 1644 is understood across different contexts — never implying one meaning because of another.
- Mathematics
Beijing was taken by rebels and then by the Manchus, who founded the Qing dynasty and ruled until 1912. A rebellion succeeded and its leader lost the resulting empire within weeks.
- History
In 1644, the Qing dynasty took Beijing, ending Ming rule (China).
- Science
In 1644, Evangelista Torricelli's mercury column showed that the atmosphere has weight, and that a vacuum can exist above the mercury (Italy).
1644 is part of
Factors & digit properties
- Divisors (12)
- 1, 2, 3, 4, 6, 12, 137, 274, 411, 548, 822, 1644
- Prime factorisation
- 2^2 × 3 × 137
- Digit sum
- 15
- Digital root
- 6
Representations
- Decimal
- 1644
- Scientific notation
- 1.644 × 10^3
Roman numerals
M D C X L I V
MDCXLIV uses the subtractive pair IV: one before five — five minus one.
Binary
1 1 0 0 1 1 0 1 1 0 0
1 × 1,024 + 1 × 512 + 0 × 256 + 0 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 0 × 2 + 0 × 1 = 1,644
Octal
3 1 5 4
3 × 512 + 1 × 64 + 5 × 8 + 4 × 1 = 1,644
Hexadecimal
6 6 c
6 × 256 + 6 × 16 + c × 1 = 1,644
Read as powers of two: 1,024 + 512 + 64 + 32 + 8 + 4 = 1,644.
In historical numeral systems
Egyptian
1 lotus, 6 coils of rope, 4 hobbles, 4 strokes
1 × 1,000 + 6 × 100 + 4 × 10 + 4 × 1 = 1,644. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
2 corner wedges + 7 vertical wedges (sixties place), 2 corner wedges + 4 vertical wedges (units place)
27 × 60 + 24 = 1644. 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
- Abundant number
Related numbers & connections
1644 is a year in the 17th century, in the 1640s.
The Zhou dynasty from around 1046 BC introduced the Mandate of Heaven, and every subsequent dynastic overthrow invoked it — including the Ming collapse in 1644.
View 1046 →Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
Other connections
- is associated with1046
why?
Strength 0.50, confidence "high".
History
In 1644, the Qing dynasty took Beijing, ending Ming rule (China).
DocumentedHistoryGeography: ChinaPeriod: 1644Li Zicheng's rebellion took Beijing in 1644 and the last Ming emperor killed himself. The Manchus then entered through a pass opened by a Ming general and kept the empire for 268 years.
DocumentedHistoryGeography: ChinaPeriod: 1644
Science
In 1644, Evangelista Torricelli's mercury column showed that the atmosphere has weight, and that a vacuum can exist above the mercury (Italy).
DocumentedScienceGeography: ItalyPeriod: 1644
Common questions
Is 1644 a prime number?
No, 1644 is not prime.
What are the factors of 1644?
The factors of 1644 are 1, 2, 3, 4, 6, 12, 137, 274, 411, 548, 822, 1644.
What is 1644 in Roman numerals?
1644 in Roman numerals is MDCXLIV. IV is subtractive: one before five — five minus one. Written additively it would be MDCXXXXIIII, 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