1931
1931 is the year the Empire State Building was completed.
- Odd
- Prime
Where 1931 fits
Why 1931 is special
It went up in 410 days during the Depression and stood as the world's tallest building for nearly forty years. It was largely empty for its first decade, earning the nickname the Empty State Building.
1931 is part of
Factors & digit properties
- Divisors (2)
- 1, 1931
- Prime factorisation
- 1931
- Digit sum
- 14
- Digital root
- 5
Representations
- Decimal
- 1931
- Binary
- 11110001011
- Octal
- 3613
- Hexadecimal
- 78b
- Roman numeral
- MCMXXXI
- Scientific notation
- 1.931 × 10^3
Other mathematical patterns
- Deficient number
- Sophie Germain prime
- Twin prime
Related numbers & connections
Cheap steel from 1856 made tall buildings structurally possible, and the Empire State Building of 1931 is among the results — finished in 410 days and largely empty for a decade.
View 1856 →Other connections
- developed from1856
why?
Strength 0.50, confidence "high".
Finance & economics
The Empire State Building was finished in 410 days and then struggled to find tenants through the 1930s. Being the tallest structure in the world and being a viable investment turned out to be unrelated properties.
DocumentedFinance & economicsGeography: New York, United StatesPeriod: 1931
Common questions
Is 1931 a prime number?
Yes, 1931 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 1931?
The factors of 1931 are 1, 1931.
What is 1931 in Roman numerals?
1931 in Roman numerals is MCMXXXI.
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