205
The Peugeot 205 T16 was a Group B rally car sold as a road car to qualify.
- Odd
- Composite
Where 205 fits
Why 205 is special
Two hundred were built for homologation and shared almost nothing with the ordinary 205 beyond the silhouette — the engine was moved to the middle and the drivetrain replaced entirely.
Factors & digit properties
- Divisors (4)
- 1, 5, 41, 205
- Prime factorisation
- 5 × 41
- Digit sum
- 7
- Digital root
- 7
Representations
- Decimal
- 205
- Scientific notation
- 2.050 × 10^2
Roman numerals
C C V
Binary
1 1 0 0 1 1 0 1
1 × 128 + 1 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 0 × 2 + 1 × 1 = 205
Octal
3 1 5
3 × 64 + 1 × 8 + 5 × 1 = 205
Hexadecimal
c d
c × 16 + d × 1 = 205
Read as powers of two: 128 + 64 + 8 + 4 + 1 = 205.
In historical numeral systems
Egyptian
2 coils of rope, 5 strokes
2 × 100 + 5 × 1 = 205. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 vertical wedges (sixties place), 2 corner wedges + 5 vertical wedges (units place)
3 × 60 + 25 = 205. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
sigma, then epsilon, marked as a numeral
sigma-epsilon + keraia
sigma + epsilon written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
resh, then he
resh-he
resh (200) + he (5) = 205, written in descending order.
Maya
2 bars (upper, twenties place) over 1 bar (lower, units place)
10 × 20 + 5 = 205. 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
- Semiprime
- Lucky number (mathematical sieve)
Related numbers & connections
The 190E's touring car programme and the 205 T16's rally programme were both funded substantially to sell the road cars they resembled.
View 190 →Technology & computing
The 205 T16 looked like the family hatchback and was mid-engined with all-wheel drive underneath. Homologation rules produced a series of cars that resembled ordinary models and shared no engineering with them.
DocumentedTechnology & computingGeography: FrancePeriod: 1984
Common questions
Is 205 a prime number?
No, 205 is not prime.
What are the factors of 205?
The factors of 205 are 1, 5, 41, 205.
What is 205 in Roman numerals?
205 in Roman numerals is CCV.
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