317
The LM317 is an adjustable voltage regulator.
- Odd
- Prime
Where 317 fits
Why 317 is special
Two resistors set the output anywhere from about 1.25 volts upward, which replaced a shelf of fixed regulators with one part.
317 is part of
Factors & digit properties
- Divisors (2)
- 1, 317
- Prime factorisation
- 317
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 317
- Scientific notation
- 3.170 × 10^2
Roman numerals
C C C X V I I
Binary
1 0 0 1 1 1 1 0 1
1 × 256 + 0 × 128 + 0 × 64 + 1 × 32 + 1 × 16 + 1 × 8 + 1 × 4 + 0 × 2 + 1 × 1 = 317
Octal
4 7 5
4 × 64 + 7 × 8 + 5 × 1 = 317
Hexadecimal
1 3 d
1 × 256 + 3 × 16 + d × 1 = 317
Read as powers of two: 256 + 32 + 16 + 8 + 4 + 1 = 317.
In historical numeral systems
Egyptian
3 coils of rope, 1 hobble, 7 strokes
3 × 100 + 1 × 10 + 7 × 1 = 317. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
5 vertical wedges (sixties place), 1 corner wedge + 7 vertical wedges (units place)
5 × 60 + 17 = 317. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
tau, then iota, then zeta, marked as a numeral
tau-iota-zeta + keraia
tau + iota + zeta written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
shin, then yod, then zayin
shin-yod-zayin
shin (300) + yod (10) + zayin (7) = 317, written in descending order.
Maya
3 bars (upper, twenties place) over 3 bars + 2 dots (lower, units place)
15 × 20 + 17 = 317. Places stack vertically with the smallest at the bottom, so the upper group is worth twenty times the lower.
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
Related numbers & connections
The pair provides the positive and negative rails that operational amplifier circuits require.
View 337 →The LM317 sets its output with two resistors where the 7805 is fixed, which replaced a shelf of parts with one.
View 7805 →Technology & computing
The LM317 maintains a constant 1.25 volts between its output and adjust terminals, so an external resistor divider sets the output voltage across a wide range.
DocumentedTechnology & computingPeriod: 1970s–
Common questions
Is 317 a prime number?
Yes, 317 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 317?
The factors of 317 are 1, 317.
What is 317 in Roman numerals?
317 in Roman numerals is CCCXVII.
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