1865
1865 is the year the American Civil War ended and slavery was abolished in the United States.
- Odd
- Composite
Where 1865 fits
Why 1865 is special
Lee surrendered at Appomattox in April, Lincoln was assassinated five days later, and the Thirteenth Amendment was ratified in December. The compression of those events into one year is why 1865 rather than 1863 is the date that closes the period.
Same number, different meanings
How 1865 is understood across different contexts — never implying one meaning because of another.
- Mathematics
Lee surrendered at Appomattox in April, Lincoln was assassinated five days later, and the Thirteenth Amendment was ratified in December. The compression of those events into one year is why 1865 rather than 1863 is the date that closes the period.
- History
In 1865, the American Civil War ended and Abraham Lincoln was assassinated (North America).
- Science
In 1865, Gregor Mendel presented the inheritance patterns he had found in pea plants, work that was largely ignored for thirty-five years (Moravia).
1865 is part of
Factors & digit properties
- Divisors (4)
- 1, 5, 373, 1865
- Prime factorisation
- 5 × 373
- Digit sum
- 20
- Digital root
- 2
Representations
- Decimal
- 1865
- Scientific notation
- 1.865 × 10^3
Roman numerals
M D C C C L X V
Binary
1 1 1 0 1 0 0 1 0 0 1
1 × 1,024 + 1 × 512 + 1 × 256 + 0 × 128 + 1 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 1,865
Octal
3 5 1 1
3 × 512 + 5 × 64 + 1 × 8 + 1 × 1 = 1,865
Hexadecimal
7 4 9
7 × 256 + 4 × 16 + 9 × 1 = 1,865
Read as powers of two: 1,024 + 512 + 256 + 64 + 8 + 1 = 1,865.
In historical numeral systems
Egyptian
1 lotus, 8 coils of rope, 6 hobbles, 5 strokes
1 × 1,000 + 8 × 100 + 6 × 10 + 5 × 1 = 1,865. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges + 1 vertical wedge (sixties place), 5 vertical wedges (units place)
31 × 60 + 5 = 1865. 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
1865 is a year in the 19th century, in the 1860s.
The American Civil War ran from 1861 to 1865, and 1865 rather than the 1863 Emancipation Proclamation is the date that closes the period, because that is when the Thirteenth Amendment was ratified.
View 1861 →Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
Other connections
- is associated with1861
why?
Strength 0.50, confidence "high".
History
In 1865, the American Civil War ended and Abraham Lincoln was assassinated (North America).
DocumentedHistoryGeography: North AmericaPeriod: 1865Lee surrendered at Appomattox in April 1865, Lincoln was assassinated five days later, and the Thirteenth Amendment abolishing slavery was ratified in December. The compression of those into a single year is why 1865 rather than the 1863 Emancipation Proclamation is the date that closes the period.
DocumentedHistoryGeography: United StatesPeriod: 1865
Science
In 1865, Gregor Mendel presented the inheritance patterns he had found in pea plants, work that was largely ignored for thirty-five years (Moravia).
DocumentedScienceGeography: MoraviaPeriod: 1865
Common questions
Is 1865 a prime number?
No, 1865 is not prime.
What are the factors of 1865?
The factors of 1865 are 1, 5, 373, 1865.
What is 1865 in Roman numerals?
1865 in Roman numerals is MDCCCLXV.
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