8081
Port 8081 is the overflow when 8080 is taken.
- Odd
- Prime
Where 8081 fits
Why 8081 is special
It has no protocol of its own; it exists because developers running two services need a second unprivileged port. Whole conventions form around what is simply the next number up.
8081 is part of
Factors & digit properties
- Divisors (2)
- 1, 8081
- Prime factorisation
- 8081
- Digit sum
- 17
- Digital root
- 8
Representations
- Decimal
- 8081
- Scientific notation
- 8.081 × 10^3
Roman numerals
Roman numerals as modelled here goes up to 3,999.
Binary
1 1 1 1 1 1 0 0 1 0 0 0 1
1 × 4,096 + 1 × 2,048 + 1 × 1,024 + 1 × 512 + 1 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 0 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 8,081
Octal
1 7 6 2 1
1 × 4,096 + 7 × 512 + 6 × 64 + 2 × 8 + 1 × 1 = 8,081
Hexadecimal
1 f 9 1
1 × 4,096 + f × 256 + 9 × 16 + 1 × 1 = 8,081
Read as powers of two: 4,096 + 2,048 + 1,024 + 512 + 256 + 128 + 16 + 1 = 8,081.
In historical numeral systems
Egyptian
8 lotuses, 8 hobbles, 1 stroke
8 × 1,000 + 8 × 10 + 1 × 1 = 8,081. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Systems that simply cannot reach this value are left out. Where a script needs a font most readers do not have, the reading is given instead of the glyphs — see number systems for each system in full.
Other mathematical patterns
- Deficient number
- Happy number
Related numbers & connections
AJP on 8009 connects a web server to Tomcat and was enabled by default for years, which turned into file disclosure when Ghostcat was published in 2020.
View 8009 →Technology & computing
8081 is not assigned to anything in particular. It is what people use when 8080 is occupied, and the convention is now stable enough that proxies and documentation assume it.
DocumentedTechnology & computing
Common questions
Is 8081 a prime number?
Yes, 8081 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 8081?
The factors of 8081 are 1, 8081.
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: 15 July 2026