1643
1643 is the year the barometer was invented.
- Odd
- Composite
Where 1643 fits
Why 1643 is special
Torricelli filled a tube with mercury and produced a vacuum above it, which was thought impossible. Measuring air pressure and demonstrating that a vacuum can exist were the same experiment.
Same number, different meanings
How 1643 is understood across different contexts — never implying one meaning because of another.
- Mathematics
Torricelli filled a tube with mercury and produced a vacuum above it, which was thought impossible. Measuring air pressure and demonstrating that a vacuum can exist were the same experiment.
- Technology & computing
In 1643, Evangelista Torricelli demonstrated the mercury barometer (Italy).
- Science
Torricelli's 1643 mercury column both measured atmospheric pressure and produced the first sustained laboratory vacuum, contradicting the doctrine that nature abhors one.
1643 is part of
Factors & digit properties
- Divisors (4)
- 1, 31, 53, 1643
- Prime factorisation
- 31 × 53
- Digit sum
- 14
- Digital root
- 5
Representations
- Decimal
- 1643
- Scientific notation
- 1.643 × 10^3
Roman numerals
M D C X L I I I
MDCXLIII uses the subtractive pair XL: ten before fifty — fifty minus ten.
Binary
1 1 0 0 1 1 0 1 0 1 1
1 × 1,024 + 1 × 512 + 0 × 256 + 0 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 1,643
Octal
3 1 5 3
3 × 512 + 1 × 64 + 5 × 8 + 3 × 1 = 1,643
Hexadecimal
6 6 b
6 × 256 + 6 × 16 + b × 1 = 1,643
Read as powers of two: 1,024 + 512 + 64 + 32 + 8 + 2 + 1 = 1,643.
In historical numeral systems
Egyptian
1 lotus, 6 coils of rope, 4 hobbles, 3 strokes
1 × 1,000 + 6 × 100 + 4 × 10 + 3 × 1 = 1,643. 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 + 3 vertical wedges (units place)
27 × 60 + 23 = 1643. 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
1643 is a year in the 17th century, in the 1640s.
Torricelli produced a sustained vacuum in 1643, contradicting the doctrine that nature abhors one. The Royal Society, chartered in 1662, was founded on exactly that preference for demonstration over authority.
View 1662 →Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
Other connections
- developed from1662
why?
Strength 0.50, confidence "high".
Technology & computing
In 1643, Evangelista Torricelli demonstrated the mercury barometer (Italy).
DocumentedTechnology & computingGeography: ItalyPeriod: 1643
Science
Torricelli's 1643 mercury column both measured atmospheric pressure and produced the first sustained laboratory vacuum, contradicting the doctrine that nature abhors one.
DocumentedScienceGeography: ItalyPeriod: 1643
Common questions
Is 1643 a prime number?
No, 1643 is not prime.
What are the factors of 1643?
The factors of 1643 are 1, 31, 53, 1643.
What is 1643 in Roman numerals?
1643 in Roman numerals is MDCXLIII. XL is subtractive: ten before fifty — fifty minus ten. Written additively it would be MDCXXXXIII, 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