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.
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
- Binary
- 11100011100
- Octal
- 3434
- Hexadecimal
- 71c
- Roman numeral
- MDCCCXX
- Scientific notation
- 1.820 × 10^3
Other mathematical patterns
- Abundant number
- Pentagonal number
Related numbers & connections
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 →Other connections
- contrasts with1911
why?
Strength 0.50, confidence "high".
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: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 3 August 2026