631
Port 631 carries IPP, the Internet Printing Protocol.
- Odd
- Prime
Where 631 fits
Why 631 is special
IPP is why a printer on the network appears by itself on a laptop that has never met it. The same discovery convenience means an exposed 631 advertises a device and its capabilities to anyone who asks, which has produced a recurring genre of prank print jobs on university networks.
Same number, different meanings
How 631 is understood across different contexts — never implying one meaning because of another.
- Mathematics
IPP is why a printer on the network appears by itself on a laptop that has never met it. The same discovery convenience means an exposed 631 advertises a device and its capabilities to anyone who asks, which has produced a recurring genre of prank print jobs on university networks.
- Everyday life
E631 disodium inosinate is used with glutamates, with which it acts synergistically. It is commonly produced from fish or meat, which affects its acceptability in some diets.
- Technology & computing
IPP is why a network printer shows up on a laptop that has never been configured for it. The same discovery mechanism means an exposed port 631 announces the device to anyone who asks, which universities rediscover every few years.
631 is part of
Factors & digit properties
- Divisors (2)
- 1, 631
- Prime factorisation
- 631
- Digit sum
- 10
- Digital root
- 1
Representations
- Decimal
- 631
- Scientific notation
- 6.310 × 10^2
Roman numerals
D C X X X I
Binary
1 0 0 1 1 1 0 1 1 1
1 × 512 + 0 × 256 + 0 × 128 + 1 × 64 + 1 × 32 + 1 × 16 + 0 × 8 + 1 × 4 + 1 × 2 + 1 × 1 = 631
Octal
1 1 6 7
1 × 512 + 1 × 64 + 6 × 8 + 7 × 1 = 631
Hexadecimal
2 7 7
2 × 256 + 7 × 16 + 7 × 1 = 631
Read as powers of two: 512 + 64 + 32 + 16 + 4 + 2 + 1 = 631.
In historical numeral systems
Egyptian
6 coils of rope, 3 hobbles, 1 stroke
6 × 100 + 3 × 10 + 1 × 1 = 631. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
1 corner wedge (sixties place), 3 corner wedges + 1 vertical wedge (units place)
10 × 60 + 31 = 631. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
chi, then lambda, then alpha, marked as a numeral
chi-lambda-alpha + keraia
chi + lambda + 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 resh, then lamed, then alef
tav-resh-lamed-alef
tav (400) + resh (200) + lamed (30) + alef (1) = 631, 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
- Lucky number (mathematical sieve)
Related numbers & connections
LPD dates from Berkeley Unix and IPP replaced it. Printers still answer on both, which is why printer fleets are a standing security finding.
View 515 →Everyday life
E631 disodium inosinate is used with glutamates, with which it acts synergistically. It is commonly produced from fish or meat, which affects its acceptability in some diets.
DocumentedEveryday lifeGeography: European Union and states adopting the E number systemPeriod: 1962–
Technology & computing
IPP is why a network printer shows up on a laptop that has never been configured for it. The same discovery mechanism means an exposed port 631 announces the device to anyone who asks, which universities rediscover every few years.
DocumentedTechnology & computing
Common questions
Is 631 a prime number?
Yes, 631 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 631?
The factors of 631 are 1, 631.
What is 631 in Roman numerals?
631 in Roman numerals is DCXXXI.
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