N
NumberPedia
Menu

© 2025 NumberPedia

Composite Number

105

105 is a odd composite number that follows 104 and precedes 106. It is composed of 8 distinct factors: 1, 3, 5, 7, 15, 21, 35, 105. Its prime factorization can be written as 3 × 5 × 7. 105 is classified as a deficient number based on the sum of its proper divisors. In computer science, 105 is represented as 1101001 in binary and 69 in hexadecimal. Historically, it is written as CV in Roman numerals. It also belongs to the triangular number sequence.

Roman Numeral
CV
LatinClassic
Binary
1101001
Base 2
Hexadecimal
69
Base 16

Factor Analysis

8 Factors

Properties

ParityOdd
Perfect SquareNo
Perfect CubeNo
Digit Count3
Digit Sum6
Digital Root6
Sum of Factors192
Aliquot Sum87
ClassificationDeficient
Prime Factors3
SequencesComposite numbers, Deficient numbers
Prime Factorization

The prime factorization (3 × 5 × 7) reveals 3 prime building blocks.

Canonical form
3 × 5 × 7
357
Divisibility Insights
  • Divisible by 2

    105 ends in 5, so it is odd.

  • Divisible by 3

    The digit sum 6 is a multiple of 3.

  • Divisible by 4

    The last two digits 05 are not divisible by 4.

  • Divisible by 5

    105 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 6 is not a multiple of 9.

  • Divisible by 10

    105 does not end in 0.

  • Divisible by 11

    The alternating digit sum 6 is not a multiple of 11.

Sequence Membership

Deficient classification and digit analytics place 105 within several notable number theory sequences:

Composite numbersDeficient numbersTriangular numbers
Advertisement

Deep dive

How 105 breaks down

105 carries 8 distinct factors and a digit signature of 6 (6 as the digital root). The deficient classification indicates that its proper divisors sum to 87, which stays below the number, offering a quick glimpse into its abundance profile.

Numeral conversions provide additional context: the binary form 1101001 supports bitwise reasoning, hexadecimal 69 aligns with computing notation, and the Roman numeral CV keeps the encyclopedic tradition alive. These attributes make 105 useful for math olympiad problems, puzzle design, and code challenges alike.

Context

Where 105 shows up

Engineers lean on the divisibility profile when sizing circuits, mod designers use neighboring values (100110) to tune search ranges, and educators feature 105 in worksheets about factor trees. Its binary footprint of length 7 bits also makes it a solid example for teaching storage limits and overflow.

Beyond STEM, the classification and sequence tags (Composite numbers, Deficient numbers, Triangular numbers) help historians, numerologists, and trivia writers tie 105 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 105

Is 105 a prime number?

105 is composite with 8 total factors and the prime factorization 3 × 5 × 7.

What is the prime factorization of 105?

It breaks down as 3 × 5 × 7, multiplying the primes 3 × 5 × 7.

How is 105 represented in binary and hexadecimal?

105 converts to 1101001 in binary and 69 in hexadecimal, which are helpful for computer science applications.

Is 105 a perfect square, cube, or triangular number?

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

What are the digit sum and digital root of 105?

The digits sum to 6, producing a digital root of 6. These tests power divisibility shortcuts for 3 and 9.