501
501 is the starting score in a standard game of darts, counted down to exactly zero.
- Odd
- Composite
Where 501 fits
Why 501 is special
501 is chosen to be awkward. Players count down from it and must finish on a double, so the odd starting total means the last dart cannot simply halve a round number — it forces a checkout to be planned several throws ahead. The highest possible finish is 170: treble 20, treble 20, bullseye.
501 is part of
Factors & digit properties
- Divisors (4)
- 1, 3, 167, 501
- Prime factorisation
- 3 × 167
- Digit sum
- 6
- Digital root
- 6
Representations
- Decimal
- 501
- Binary
- 111110101
- Octal
- 765
- Hexadecimal
- 1f5
- Roman numeral
- DI
- Scientific notation
- 5.010 × 10^2
Other mathematical patterns
- Deficient number
- Semiprime
Related numbers & connections
The two numbers a darts commentator says most. 501 is where every leg starts and 180 is the maximum a single visit can score, so the game is largely the arithmetic of getting from one to the other and still finishing on a double.
View 180 →501 is the score every darts leg starts from, and the reason the maximum three-dart visit of 180 matters as much as it does.
Numbers Around Us
- appears alongside180
why?
Strength 0.50, confidence "high".
Other connections
- is associated withMaximum three-dart score
why?
Strength 0.50, confidence "high".
Sport
A game of darts must finish on a double, so the closing throw is constrained rather than free. Starting from 501 rather than 500 means the total is odd, so a player cannot simply halve their way down and must plan a checkout several darts ahead — the arithmetic is part of the skill. The highest possible finish is 170.
DocumentedSport
Common questions
Is 501 a prime number?
No, 501 is not prime.
What are the factors of 501?
The factors of 501 are 1, 3, 167, 501.
What is 501 in Roman numerals?
501 in Roman numerals is DI.
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: 3 August 2026