1921
1921 is the year insulin was isolated.
- Odd
- Composite
Where 1921 fits
Why 1921 is special
Diabetes went from fatal to manageable within about a year of the first human trial. The discoverers sold the patent for one dollar each, intending that nobody should profit from it — a decision whose consequences are debated in every subsequent argument about insulin pricing.
Factors & digit properties
- Divisors (4)
- 1, 17, 113, 1921
- Prime factorisation
- 17 × 113
- Digit sum
- 13
- Digital root
- 4
Representations
- Decimal
- 1921
- Binary
- 11110000001
- Octal
- 3601
- Hexadecimal
- 781
- Roman numeral
- MCMXXI
- Scientific notation
- 1.921 × 10^3
Other mathematical patterns
- Deficient number
- Semiprime
- Lucky number (mathematical sieve)
Related numbers & connections
Insulin's discoverers sold the patent for a dollar in 1921 and Salk declined to patent the polio vaccine in 1955. Both decisions are cited in every modern argument about drug pricing.
View 1955 →Science
Insulin's discoverers transferred the patent to the University of Toronto for a nominal dollar so it could not be monopolised. That the drug is now among the most contested in pricing debates is a direct commentary on how little a patent decision constrains a market a century later.
DocumentedScienceGeography: CanadaPeriod: 1921
Common questions
Is 1921 a prime number?
No, 1921 is not prime.
What are the factors of 1921?
The factors of 1921 are 1, 17, 113, 1921.
What is 1921 in Roman numerals?
1921 in Roman numerals is MCMXXI.
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