1945
1945 is the year the Second World War ended and the United Nations was founded.
- Odd
- Composite
Where 1945 fits
Why 1945 is special
1945 is where the modern international order starts. Germany surrendered in May, the atomic bombings of Hiroshima and Nagasaki came in August followed by Japan's surrender, and the United Nations Charter was signed in June and took effect in October. The Nuremberg trials began in November, establishing that individuals could be prosecuted for state acts.
Same number, different meanings
How 1945 is understood across different contexts — never implying one meaning because of another.
- Mathematics
1945 is where the modern international order starts. Germany surrendered in May, the atomic bombings of Hiroshima and Nagasaki came in August followed by Japan's surrender, and the United Nations Charter was signed in June and took effect in October. The Nuremberg trials began in November, establishing that individuals could be prosecuted for state acts.
- History
The war in Europe ended in May 1945 and in the Pacific in September. The United Nations Charter was signed in June of the same year, so the institutions built to prevent a recurrence date from the months in which the conflict was still ending.
- Law & regulation
The Nuremberg trials, opening in November 1945, established that a person could be prosecuted for acts committed on behalf of a state — that following orders was not by itself a defence. Together with the UN Charter signed in June, it is why 1945 marks the start of the modern international legal order rather than merely the end of a war.
Factors & digit properties
- Divisors (4)
- 1, 5, 389, 1945
- Prime factorisation
- 5 × 389
- Digit sum
- 19
- Digital root
- 1
Representations
- Decimal
- 1945
- Binary
- 11110011001
- Octal
- 3631
- Hexadecimal
- 799
- Roman numeral
- MCMXLV
- Scientific notation
- 1.945 × 10^3
Other mathematical patterns
- Deficient number
- Semiprime
- Lucky number (mathematical sieve)
Related numbers & connections
Four years separate the end of the war from the settlement that defined the next four decades: NATO, the People's Republic of China, and the first Soviet atomic test.
View 1949 →The League of Nations began work in 1920 without the country that proposed it; the United Nations from 1945 was designed around that failure.
View 1920 →Numbers Around Us
History
The war in Europe ended in May 1945 and in the Pacific in September. The United Nations Charter was signed in June of the same year, so the institutions built to prevent a recurrence date from the months in which the conflict was still ending.
DocumentedHistoryGeography: GlobalPeriod: 1945
Law & regulation
The Nuremberg trials, opening in November 1945, established that a person could be prosecuted for acts committed on behalf of a state — that following orders was not by itself a defence. Together with the UN Charter signed in June, it is why 1945 marks the start of the modern international legal order rather than merely the end of a war.
DocumentedLaw & regulationGeography: Nuremberg, Allied-occupied Germany; the principles adopted internationally thereafterPeriod: 1945
Common questions
Is 1945 a prime number?
No, 1945 is not prime.
What are the factors of 1945?
The factors of 1945 are 1, 5, 389, 1945.
What is 1945 in Roman numerals?
1945 in Roman numerals is MCMXLV.
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: 3 August 2026