1980
1980 is the year smallpox was declared eradicated.
- Even
- Composite
Where 1980 fits
Why 1980 is special
It is the only human disease ever eliminated, after a campaign built on ring vaccination rather than vaccinating everyone. The last natural case was in Somalia in 1977; the last death was a laboratory accident in Birmingham in 1978.
Factors & digit properties
- Divisors (36)
- 1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 15, 18, 20, 22, 30, 33, 36, 44, 45, 55, 60, 66, 90, 99, 110, 132, 165, 180, 198, 220, 330, 396, 495, 660, 990, 1980
- Prime factorisation
- 2^2 × 3^2 × 5 × 11
- Digit sum
- 18
- Digital root
- 9
Representations
- Decimal
- 1980
- Binary
- 11110111100
- Octal
- 3674
- Hexadecimal
- 7bc
- Roman numeral
- MCMLXXX
- Scientific notation
- 1.980 × 10^3
Other mathematical patterns
- Abundant number
- Harshad (Niven) number
Related numbers & connections
Smallpox eradication and the Montreal Protocol. Both are cases of coordinated international action achieving a measurable, verifiable result.
View 1987 →Smallpox was declared eradicated in 1980, 184 years after Jenner's vaccination experiment. It remains the only human disease eliminated.
View 1796 →Science
Smallpox is the sole human disease eradicated, achieved by ring vaccination around outbreaks rather than vaccinating everyone. The last natural case was in Somalia in 1977; the last death was a British laboratory accident in 1978.
DocumentedSciencePeriod: 1980
Common questions
Is 1980 a prime number?
No, 1980 is not prime.
What are the factors of 1980?
The factors of 1980 are 1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 15, 18, 20, 22, 30, 33, 36, 44, 45, 55, 60, 66, 90, 99, 110, 132, 165, 180, 198, 220, 330, 396, 495, 660, 990, 1980.
What is 1980 in Roman numerals?
1980 in Roman numerals is MCMLXXX.
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