1123
RFC 1123 lists the requirements for internet host application software.
- Odd
- Prime
Where 1123 fits
Why 1123 is special
It is the document that quietly permitted hostnames beginning with a digit, which is why 3com.com is a legal name.
Same number, different meanings
How 1123 is understood across different contexts — never implying one meaning because of another.
- Mathematics
It is the document that quietly permitted hostnames beginning with a digit, which is why 3com.com is a legal name.
- History
In 1123, the First Lateran Council became the first general council held in the West (Europe).
- Technology & computing
RFC 1123 amends and clarifies earlier application-level specifications rather than replacing them, including the relaxation of the hostname rule set in RFC 952.
1123 is part of
Factors & digit properties
- Divisors (2)
- 1, 1123
- Prime factorisation
- 1123
- Digit sum
- 7
- Digital root
- 7
Representations
- Decimal
- 1123
- Scientific notation
- 1.123 × 10^3
Roman numerals
M C X X I I I
Binary
1 0 0 0 1 1 0 0 0 1 1
1 × 1,024 + 0 × 512 + 0 × 256 + 0 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 1,123
Octal
2 1 4 3
2 × 512 + 1 × 64 + 4 × 8 + 3 × 1 = 1,123
Hexadecimal
4 6 3
4 × 256 + 6 × 16 + 3 × 1 = 1,123
Read as powers of two: 1,024 + 64 + 32 + 2 + 1 = 1,123.
In historical numeral systems
Egyptian
1 lotus, 1 coil of rope, 2 hobbles, 3 strokes
1 × 1,000 + 1 × 100 + 2 × 10 + 3 × 1 = 1,123. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
1 corner wedge + 8 vertical wedges (sixties place), 4 corner wedges + 3 vertical wedges (units place)
18 × 60 + 43 = 1123. Places are separated by a space on the tablet, with the higher place written first.
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
- Lucky number (mathematical sieve)
Related numbers & connections
1123 is a year in the 12th century, in the 1120s.
RFC 952 forbade hostnames beginning with a digit and RFC 1123 relaxed the rule, which is why 3com.com is legal.
View 952 →History
In 1123, the First Lateran Council became the first general council held in the West (Europe).
DocumentedHistoryGeography: EuropePeriod: 1123
Technology & computing
RFC 1123 amends and clarifies earlier application-level specifications rather than replacing them, including the relaxation of the hostname rule set in RFC 952.
DocumentedTechnology & computingGeography: International — IETFPeriod: 1989
Common questions
Is 1123 a prime number?
Yes, 1123 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 1123?
The factors of 1123 are 1, 1123.
What is 1123 in Roman numerals?
1123 in Roman numerals is MCXXIII.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026