1820
1820 is the year Antarctica was first sighted.
- Even
- Composite
Where 1820 fits
Why 1820 is special
Three expeditions — Russian, British and American — claimed sightings within months of each other, and priority is still argued. No one landed for another twenty years.
1820 connects to:
- historical years — appears in
- 1911 — contrasts with
Same number, different meanings
How 1820 is understood across different contexts — never implying one meaning because of another.
- Mathematics
Three expeditions — Russian, British and American — claimed sightings within months of each other, and priority is still argued. No one landed for another twenty years.
- Science
In 1820, Hans Christian Ørsted showed that electric current deflects a compass needle, linking electricity and magnetism (Denmark).
- Geography
Russian, British and American expeditions all reported sighting Antarctica in 1820, and which came first remains contested. The continent was seen by several parties before anyone set foot on it.
1820 is part of
Factors & digit properties
- Divisors (24)
- 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910, 1820
- Prime factorisation
- 2^2 × 5 × 7 × 13
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 1820
- Scientific notation
- 1.820 × 10^3
Roman numerals
M D C C C X X
Binary
1 1 1 0 0 0 1 1 1 0 0
1 × 1,024 + 1 × 512 + 1 × 256 + 0 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 1 × 8 + 1 × 4 + 0 × 2 + 0 × 1 = 1,820
Octal
3 4 3 4
3 × 512 + 4 × 64 + 3 × 8 + 4 × 1 = 1,820
Hexadecimal
7 1 c
7 × 256 + 1 × 16 + c × 1 = 1,820
Read as powers of two: 1,024 + 512 + 256 + 16 + 8 + 4 = 1,820.
In historical numeral systems
Egyptian
1 lotus, 8 coils of rope, 2 hobbles
1 × 1,000 + 8 × 100 + 2 × 10 = 1,820. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges (sixties place), 2 corner wedges (units place)
30 × 60 + 20 = 1820. 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
- Pentagonal number
Related numbers & connections
1820 is a year in the 19th century, in the 1820s.
Antarctica was first sighted in 1820 by three expeditions within months, and Amundsen reached the pole in 1911. Ninety-one years separate seeing the continent from crossing it.
View 1911 →Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
Other connections
- contrasts with1911
why?
Strength 0.50, confidence "high".
Science
In 1820, Hans Christian Ørsted showed that electric current deflects a compass needle, linking electricity and magnetism (Denmark).
DocumentedScienceGeography: DenmarkPeriod: 1820
Geography
Russian, British and American expeditions all reported sighting Antarctica in 1820, and which came first remains contested. The continent was seen by several parties before anyone set foot on it.
DocumentedGeographyGeography: AntarcticaPeriod: 1820
Common questions
Is 1820 a prime number?
No, 1820 is not prime.
What are the factors of 1820?
The factors of 1820 are 1, 2, 4, 5, 7, 10, 13, 14, 20, 26, 28, 35, 52, 65, 70, 91, 130, 140, 182, 260, 364, 455, 910, 1820.
What is 1820 in Roman numerals?
1820 in Roman numerals is MDCCCXX.
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