1815
1815 is the year of the Battle of Waterloo and the close of the Congress of Vienna.
- Odd
- Composite
Where 1815 fits
Why 1815 is special
1815 ended twenty-three years of near-continuous European war. Napoleon's defeat at Waterloo in June closed the Hundred Days, and the Congress of Vienna concluded weeks earlier, redrawing borders in a settlement that kept the great powers from general war for the better part of a century. The year is also remembered for the eruption of Mount Tambora, which caused the following 'year without a summer'.
1815 is part of
Factors & digit properties
- Divisors (12)
- 1, 3, 5, 11, 15, 33, 55, 121, 165, 363, 605, 1815
- Prime factorisation
- 3 × 5 × 11^2
- Digit sum
- 15
- Digital root
- 6
Representations
- Decimal
- 1815
- Binary
- 11100010111
- Octal
- 3427
- Hexadecimal
- 717
- Roman numeral
- MDCCCXV
- Scientific notation
- 1.815 × 10^3
Other mathematical patterns
- Deficient number
- Happy number
- Harshad (Niven) number
Related numbers & connections
Two dates that mark the beginning and the end of an era of invasion anxiety in Britain — the last successful conquest of England, and the defeat that ended the last serious threat of another. Both are taught as single battles despite each being the end of a longer campaign.
View 1066 →Napoleon's Russian campaign of 1812 destroyed his army and Waterloo in 1815 ended his rule. The retreat did more damage than the final defeat.
View 1812 →Science
Mount Tambora erupted in April 1815 in the largest volcanic event of recorded history, injecting enough sulphate aerosol into the stratosphere to lower global temperatures measurably. The following year brought crop failures and snow in June across Europe and North America — a documented case of a single geological event altering a hemisphere's weather.
DocumentedSciencePeriod: 1815 – 1816
Common questions
Is 1815 a prime number?
No, 1815 is not prime.
What are the factors of 1815?
The factors of 1815 are 1, 3, 5, 11, 15, 33, 55, 121, 165, 363, 605, 1815.
What is 1815 in Roman numerals?
1815 in Roman numerals is MDCCCXV.
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