515
Port 515 carries the Line Printer Daemon protocol.
- Odd
- Composite
Where 515 fits
Why 515 is special
LPD dates from Berkeley Unix and is still spoken by office printers decades after better protocols arrived. Its persistence is the ordinary reason obsolete protocols survive: the devices work, replacing them costs money, and nobody is harmed until someone scans the network.
515 is part of
Factors & digit properties
- Divisors (4)
- 1, 5, 103, 515
- Prime factorisation
- 5 × 103
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 515
- Scientific notation
- 5.150 × 10^2
Roman numerals
D X V
Binary
1 0 0 0 0 0 0 0 1 1
1 × 512 + 0 × 256 + 0 × 128 + 0 × 64 + 0 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 515
Octal
1 0 0 3
1 × 512 + 0 × 64 + 0 × 8 + 3 × 1 = 515
Hexadecimal
2 0 3
2 × 256 + 0 × 16 + 3 × 1 = 515
Read as powers of two: 512 + 2 + 1 = 515.
In historical numeral systems
Egyptian
5 coils of rope, 1 hobble, 5 strokes
5 × 100 + 1 × 10 + 5 × 1 = 515. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
8 vertical wedges (sixties place), 3 corner wedges + 5 vertical wedges (units place)
8 × 60 + 35 = 515. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
phi, then iota, then epsilon, marked as a numeral
phi-iota-epsilon + keraia
phi + iota + epsilon 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 qof, then tet, then vav
tav-qof-tet-vav
The ordinary descending rule would give יה (yod 10 + he 5), which spells a form of the divine name, so 15 is written טו — tet (9) + vav (6) — instead.
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
- Palindromic number
- Deficient number
- Semiprime
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 631 →Other connections
- is associated with631
why?
Strength 0.50, confidence "high".
Technology & computing
LPD predates the web and remains enabled on a large share of network printers. Legacy protocols persist not because they are good but because the hardware speaking them still functions, which is why printer fleets are a standing security finding.
DocumentedTechnology & computing
Common questions
Is 515 a prime number?
No, 515 is not prime.
What are the factors of 515?
The factors of 515 are 1, 5, 103, 515.
What is 515 in Roman numerals?
515 in Roman numerals is DXV.
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