1642
1642 is the year the English Civil War began.
- Even
- Composite
Where 1642 fits
Why 1642 is special
It ended with the trial and execution of a reigning king by his own subjects, which had no European precedent. The republic that followed lasted eleven years before the monarchy returned.
Same number, different meanings
How 1642 is understood across different contexts — never implying one meaning because of another.
- Mathematics
It ended with the trial and execution of a reigning king by his own subjects, which had no European precedent. The republic that followed lasted eleven years before the monarchy returned.
- History
In 1642, the English Civil War began (England).
- Technology & computing
In 1642, Blaise Pascal built a mechanical calculator that could add and subtract by carrying tens automatically (France).
1642 is part of
Factors & digit properties
- Divisors (4)
- 1, 2, 821, 1642
- Prime factorisation
- 2 × 821
- Digit sum
- 13
- Digital root
- 4
Representations
- Decimal
- 1642
- Scientific notation
- 1.642 × 10^3
Roman numerals
M D C X L I I
MDCXLII uses the subtractive pair XL: ten before fifty — fifty minus ten.
Binary
1 1 0 0 1 1 0 1 0 1 0
1 × 1,024 + 1 × 512 + 0 × 256 + 0 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 1 × 2 + 0 × 1 = 1,642
Octal
3 1 5 2
3 × 512 + 1 × 64 + 5 × 8 + 2 × 1 = 1,642
Hexadecimal
6 6 a
6 × 256 + 6 × 16 + a × 1 = 1,642
Read as powers of two: 1,024 + 512 + 64 + 32 + 8 + 2 = 1,642.
In historical numeral systems
Egyptian
1 lotus, 6 coils of rope, 4 hobbles, 2 strokes
1 × 1,000 + 6 × 100 + 4 × 10 + 2 × 1 = 1,642. 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 + 2 vertical wedges (units place)
27 × 60 + 22 = 1642. 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
1642 is a year in the 17th century, in the 1640s.
The Grand Remonstrance passed by eleven votes in 1641 and the English Civil War began the following year.
View 1641 →History
In 1642, the English Civil War began (England).
DocumentedHistoryGeography: EnglandPeriod: 1642The conflict beginning in 1642 killed a larger share of the population of the British Isles than the First World War did, executed a king, established a republic, and ended with that king's son on the throne eighteen years later.
DocumentedHistoryGeography: England, Scotland and IrelandPeriod: 1642–1651
Technology & computing
In 1642, Blaise Pascal built a mechanical calculator that could add and subtract by carrying tens automatically (France).
DocumentedTechnology & computingGeography: FrancePeriod: 1642
Common questions
Is 1642 a prime number?
No, 1642 is not prime.
What are the factors of 1642?
The factors of 1642 are 1, 2, 821, 1642.
What is 1642 in Roman numerals?
1642 in Roman numerals is MDCXLII. XL is subtractive: ten before fifty — fifty minus ten. Written additively it would be MDCXXXXII, 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