581
K. 581 is the Clarinet Quintet.
- Odd
- Composite
Where 581 fits
Why 581 is special
It was written for a basset clarinet with extra low notes, and every standard performance transposes those passages upward because the instrument fell out of use.
Factors & digit properties
- Divisors (4)
- 1, 7, 83, 581
- Prime factorisation
- 7 × 83
- Digit sum
- 14
- Digital root
- 5
Representations
- Decimal
- 581
- Scientific notation
- 5.810 × 10^2
Roman numerals
D L X X X I
Binary
1 0 0 1 0 0 0 1 0 1
1 × 512 + 0 × 256 + 0 × 128 + 1 × 64 + 0 × 32 + 0 × 16 + 0 × 8 + 1 × 4 + 0 × 2 + 1 × 1 = 581
Octal
1 1 0 5
1 × 512 + 1 × 64 + 0 × 8 + 5 × 1 = 581
Hexadecimal
2 4 5
2 × 256 + 4 × 16 + 5 × 1 = 581
Read as powers of two: 512 + 64 + 4 + 1 = 581.
In historical numeral systems
Egyptian
5 coils of rope, 8 hobbles, 1 stroke
5 × 100 + 8 × 10 + 1 × 1 = 581. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
9 vertical wedges (sixties place), 4 corner wedges + 1 vertical wedge (units place)
9 × 60 + 41 = 581. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
phi, then pi, then alpha, marked as a numeral
phi-pi-alpha + keraia
phi + pi + 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 qof, then pe, then alef
tav-qof-pe-alef
tav (400) + qof (100) + pe (80) + alef (1) = 581, 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
Both are late works written for specific players or occasions rather than for publication.
View 543 →Other connections
- is associated with543
why?
Strength 0.50, confidence "high".
Media & popular culture
K. 581 was composed for Anton Stadler's basset clarinet with an extended lower range. Standard clarinets cannot play the original low passages, which are routinely transposed.
DocumentedMedia & popular cultureGeography: AustriaPeriod: 1789
Common questions
Is 581 a prime number?
No, 581 is not prime.
What are the factors of 581?
The factors of 581 are 1, 7, 83, 581.
What is 581 in Roman numerals?
581 in Roman numerals is DLXXXI.
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