1939
1939 is the year the Second World War began in Europe.
- Odd
- Composite
Where 1939 fits
Why 1939 is special
Germany invaded Poland on 1 September and Britain and France declared war two days later. The date marks the European opening specifically: fighting in Asia had been under way since 1937, and dating the war from 1939 is a convention that reflects a European vantage point.
Factors & digit properties
- Divisors (4)
- 1, 7, 277, 1939
- Prime factorisation
- 7 × 277
- Digit sum
- 22
- Digital root
- 4
Representations
- Decimal
- 1939
- Binary
- 11110010011
- Octal
- 3623
- Hexadecimal
- 793
- Roman numeral
- MCMXXXIX
- Scientific notation
- 1.939 × 10^3
Other mathematical patterns
- Deficient number
- Semiprime
Related numbers & connections
The conventional European dating of the Second World War, from the invasion of Poland to the surrenders of 1945. Both dates reflect a European vantage point rather than a global one.
View 1945 →The Normandy landings came five years into a war that had begun in Europe in 1939, and nearly three years after the Eastern Front opened.
View 1944 →History
Germany invaded Poland on 1 September 1939 and Britain and France declared war two days later. Dating the Second World War from 1939 reflects a European vantage point: full-scale war in Asia had been under way since Japan's invasion of China in 1937.
DocumentedHistoryGeography: EuropePeriod: 1939
Common questions
Is 1939 a prime number?
No, 1939 is not prime.
What are the factors of 1939?
The factors of 1939 are 1, 7, 277, 1939.
What is 1939 in Roman numerals?
1939 in Roman numerals is MCMXXXIX.
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