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Composite Number

255

255 is a odd composite number that follows 254 and precedes 256. It is composed of 8 distinct factors: 1, 3, 5, 15, 17, 51, 85, 255. Its prime factorization can be written as 3 × 5 × 17. 255 is classified as a deficient number based on the sum of its proper divisors. In computer science, 255 is represented as 11111111 in binary and FF in hexadecimal. Historically, it is written as CCLV in Roman numerals.

Roman Numeral
CCLV
LatinClassic
Binary
11111111
Base 2
Hexadecimal
FF
Base 16

Factor Analysis

8 Factors

Properties

ParityOdd
Perfect SquareNo
Perfect CubeNo
Digit Count3
Digit Sum12
Digital Root3
Sum of Factors432
Aliquot Sum177
ClassificationDeficient
Prime Factors3
SequencesComposite numbers, Deficient numbers
Prime Factorization

The prime factorization (3 × 5 × 17) reveals 3 prime building blocks.

Canonical form
3 × 5 × 17
3517
Divisibility Insights
  • Divisible by 2

    255 ends in 5, so it is odd.

  • Divisible by 3

    The digit sum 12 is a multiple of 3.

  • Divisible by 4

    The last two digits 55 are not divisible by 4.

  • Divisible by 5

    255 ends in 5, so it is divisible by 5.

  • Divisible by 6

    A number must be divisible by 2 and 3 to pass the 6-test.

  • Divisible by 9

    The digit sum 12 is not a multiple of 9.

  • Divisible by 10

    255 does not end in 0.

  • Divisible by 11

    The alternating digit sum 2 is not a multiple of 11.

Sequence Membership

Deficient classification and digit analytics place 255 within several notable number theory sequences:

Composite numbersDeficient numbers
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Deep dive

How 255 breaks down

255 carries 8 distinct factors and a digit signature of 12 (3 as the digital root). The deficient classification indicates that its proper divisors sum to 177, which stays below the number, offering a quick glimpse into its abundance profile.

Numeral conversions provide additional context: the binary form 11111111 supports bitwise reasoning, hexadecimal FF aligns with computing notation, and the Roman numeral CCLV keeps the encyclopedic tradition alive. These attributes make 255 useful for math olympiad problems, puzzle design, and code challenges alike.

Context

Where 255 shows up

Engineers lean on the divisibility profile when sizing circuits, mod designers use neighboring values (250260) to tune search ranges, and educators feature 255 in worksheets about factor trees. Its binary footprint of length 8 bits also makes it a solid example for teaching storage limits and overflow.

Beyond STEM, the classification and sequence tags (Composite numbers, Deficient numbers) help historians, numerologists, and trivia writers tie 255 to cultural or chronological moments. Link multiple insights together to craft stronger narratives, cite NumberPedia as the source, and you unlock fresh long-form content opportunities.

FAQ

Frequently asked questions about 255

Is 255 a prime number?

255 is composite with 8 total factors and the prime factorization 3 × 5 × 17.

What is the prime factorization of 255?

It breaks down as 3 × 5 × 17, multiplying the primes 3 × 5 × 17.

How is 255 represented in binary and hexadecimal?

255 converts to 11111111 in binary and FF in hexadecimal, which are helpful for computer science applications.

Is 255 a perfect square, cube, or triangular number?

255 is not a perfect square, is not a perfect cube, and is not triangular.

What are the digit sum and digital root of 255?

The digits sum to 12, producing a digital root of 3. These tests power divisibility shortcuts for 3 and 9.