1991
1991 is the year the Soviet Union dissolved and the World Wide Web opened to the public.
- Odd
- Composite
Where 1991 fits
Why 1991 is special
1991 ended one order and quietly began another. The USSR was formally dissolved in December after a failed August coup. In August the same year, Tim Berners-Lee posted the World Wide Web project publicly for the first time — the moment the web stopped being a CERN tool and became something anyone could join.
1991 is part of
Factors & digit properties
- Divisors (4)
- 1, 11, 181, 1991
- Prime factorisation
- 11 × 181
- Digit sum
- 20
- Digital root
- 2
Representations
- Decimal
- 1991
- Binary
- 11111000111
- Octal
- 3707
- Hexadecimal
- 7c7
- Roman numeral
- MCMXCI
- Scientific notation
- 1.991 × 10^3
Other mathematical patterns
- Palindromic number
- Deficient number
- Semiprime
Related numbers & connections
1969 carried the first ARPANET message between two machines; 1991 made the World Wide Web publicly available on the network that grew from it. The gap is the distance between a network and something to do on it.
View 1969 →The web was published in 1991 and became usable by the public in 1993, when CERN placed it in the public domain and Mosaic displayed images alongside text.
View 1993 →Technology & computing
On 6 August 1991 Tim Berners-Lee posted a summary of the World Wide Web project to a public newsgroup, with instructions for obtaining the software. That posting, rather than the 1989 proposal, is the point at which anyone outside CERN could join — four months before the Soviet Union was dissolved.
DocumentedTechnology & computingPeriod: 6 August 1991
Common questions
Is 1991 a prime number?
No, 1991 is not prime.
What are the factors of 1991?
The factors of 1991 are 1, 11, 181, 1991.
What is 1991 in Roman numerals?
1991 in Roman numerals is MCMXCI.
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