1678
1678 is the year Huygens proposed the wave theory of light.
- Even
- Composite
Where 1678 fits
Why 1678 is special
It was overshadowed by Newton's particle account for a century until interference experiments settled the matter, and then quantum mechanics made both partly right.
Same number, different meanings
How 1678 is understood across different contexts — never implying one meaning because of another.
- Mathematics
It was overshadowed by Newton's particle account for a century until interference experiments settled the matter, and then quantum mechanics made both partly right.
- History
In 1678, Huygens presented his wave theory of light, the rival to Newton's corpuscular account (Low Countries).
- Science
Huygens's wave account of 1678 lost to Newton's corpuscles for a century, was vindicated by interference experiments around 1800, and was then absorbed into a quantum description where neither picture is complete.
1678 is part of
Factors & digit properties
- Divisors (4)
- 1, 2, 839, 1678
- Prime factorisation
- 2 × 839
- Digit sum
- 22
- Digital root
- 4
Representations
- Decimal
- 1678
- Scientific notation
- 1.678 × 10^3
Roman numerals
M D C L X X V I I I
Binary
1 1 0 1 0 0 0 1 1 1 0
1 × 1,024 + 1 × 512 + 0 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 1 × 2 + 0 × 1 = 1,678
Octal
3 2 1 6
3 × 512 + 2 × 64 + 1 × 8 + 6 × 1 = 1,678
Hexadecimal
6 8 e
6 × 256 + 8 × 16 + e × 1 = 1,678
Read as powers of two: 1,024 + 512 + 128 + 8 + 4 + 2 = 1,678.
In historical numeral systems
Egyptian
1 lotus, 6 coils of rope, 7 hobbles, 8 strokes
1 × 1,000 + 6 × 100 + 7 × 10 + 8 × 1 = 1,678. 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), 5 corner wedges + 8 vertical wedges (units place)
27 × 60 + 58 = 1678. 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
1678 is a year in the 17th century, in the 1670s.
Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
History
In 1678, Huygens presented his wave theory of light, the rival to Newton's corpuscular account (Low Countries).
DocumentedHistoryGeography: Low CountriesPeriod: 1678
Science
Huygens's wave account of 1678 lost to Newton's corpuscles for a century, was vindicated by interference experiments around 1800, and was then absorbed into a quantum description where neither picture is complete.
DocumentedScienceGeography: NetherlandsPeriod: 1678
Common questions
Is 1678 a prime number?
No, 1678 is not prime.
What are the factors of 1678?
The factors of 1678 are 1, 2, 839, 1678.
What is 1678 in Roman numerals?
1678 in Roman numerals is MDCLXXVIII.
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