495
495 is Kaprekar's constant for three-digit numbers.
- Odd
- Composite
Where 495 fits
Why 495 is special
Take any three-digit number with at least two different digits, arrange the digits into the largest and smallest numbers possible, subtract, and repeat. Every starting point reaches 495 within six steps and stays there. The four-digit version of the same process converges on 6174.
Factors & digit properties
- Divisors (12)
- 1, 3, 5, 9, 11, 15, 33, 45, 55, 99, 165, 495
- Prime factorisation
- 3^2 × 5 × 11
- Digit sum
- 18
- Digital root
- 9
Representations
- Decimal
- 495
- Scientific notation
- 4.950 × 10^2
Roman numerals
C D X C V
CDXCV uses the subtractive pair XC: ten before a hundred — a hundred minus ten.
Binary
1 1 1 1 0 1 1 1 1
1 × 256 + 1 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 1 × 2 + 1 × 1 = 495
Octal
7 5 7
7 × 64 + 5 × 8 + 7 × 1 = 495
Hexadecimal
1 e f
1 × 256 + e × 16 + f × 1 = 495
Read as powers of two: 256 + 128 + 64 + 32 + 8 + 4 + 2 + 1 = 495.
In historical numeral systems
Egyptian
4 coils of rope, 9 hobbles, 5 strokes
4 × 100 + 9 × 10 + 5 × 1 = 495. 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), 1 corner wedge + 5 vertical wedges (units place)
8 × 60 + 15 = 495. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
upsilon, then koppa, then epsilon, marked as a numeral
upsilon-koppa-epsilon + keraia
upsilon + koppa + 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 tsadi, then he
tav-tsadi-he
tav (400) + tsadi (90) + he (5) = 495, 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
- Lucky number (mathematical sieve)
Related numbers & connections
Kaprekar's constants for three and four digits. The same rearrange-and-subtract routine converges on 495 from any three-digit start and on 6,174 from any four-digit one.
View 6174 →Shares a distinctive class
- is associated with6174
why?
Strength 0.50, confidence "high".
Mathematics
Arrange any three-digit number's digits into the largest and smallest values possible, subtract, repeat. Every starting point with at least two distinct digits reaches 495 within six iterations and then stays. The four-digit version of the same routine settles on 6,174.
DocumentedMathematics
Common questions
Is 495 a prime number?
No, 495 is not prime.
What are the factors of 495?
The factors of 495 are 1, 3, 5, 9, 11, 15, 33, 45, 55, 99, 165, 495.
What is 495 in Roman numerals?
495 in Roman numerals is CDXCV. XC is subtractive: ten before a hundred — a hundred minus ten. Written additively it would be CCCCLXXXXV, which Roman inscriptions used freely — the strict subtractive form is a later convention.
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