791
RFC 791 defines the Internet Protocol.
- Odd
- Composite
Where 791 fits
Why 791 is special
It is the specification that makes the internet a single network rather than many. Its 32-bit address field is the constraint everything since has worked around, and the document itself is under fifty pages.
791 is part of
Factors & digit properties
- Divisors (4)
- 1, 7, 113, 791
- Prime factorisation
- 7 × 113
- Digit sum
- 17
- Digital root
- 8
Representations
- Decimal
- 791
- Scientific notation
- 7.910 × 10^2
Roman numerals
D C C X C I
DCCXCI uses the subtractive pair XC: ten before a hundred — a hundred minus ten.
Binary
1 1 0 0 0 1 0 1 1 1
1 × 512 + 1 × 256 + 0 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 0 × 8 + 1 × 4 + 1 × 2 + 1 × 1 = 791
Octal
1 4 2 7
1 × 512 + 4 × 64 + 2 × 8 + 7 × 1 = 791
Hexadecimal
3 1 7
3 × 256 + 1 × 16 + 7 × 1 = 791
Read as powers of two: 512 + 256 + 16 + 4 + 2 + 1 = 791.
In historical numeral systems
Egyptian
7 coils of rope, 9 hobbles, 1 stroke
7 × 100 + 9 × 10 + 1 × 1 = 791. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
1 corner wedge + 3 vertical wedges (sixties place), 1 corner wedge + 1 vertical wedge (units place)
13 × 60 + 11 = 791. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
psi, then koppa, then alpha, marked as a numeral
psi-koppa-alpha + keraia
psi + koppa + alpha written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
tav, then shin, then tsadi, then alef
tav-shin-tsadi-alef
tav (400) + shin (300) + tsadi (90) + alef (1) = 791, written in descending order.
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
- Semiprime
Related numbers & connections
RFC 791 labels the IPv4 specification, the document whose 32-bit address field set the ceiling everything since has worked around.
RFC 791 defines how packets are addressed and RFC 793 how a reliable ordered stream is built on top of them. Together they are the internet's foundation.
View 793 →Technology & computing
RFC 791 defines IPv4 in under fifty pages, including the 32-bit address field that limited the internet to about 4.3 billion addresses. Almost every later networking development addresses a consequence of this document.
DocumentedTechnology & computingPeriod: 1981
Common questions
Is 791 a prime number?
No, 791 is not prime.
What are the factors of 791?
The factors of 791 are 1, 7, 113, 791.
What is 791 in Roman numerals?
791 in Roman numerals is DCCXCI. XC is subtractive: ten before a hundred — a hundred minus ten. Written additively it would be DCCLXXXXI, which Roman inscriptions used freely — the strict subtractive form is a later convention.
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