N
NumberPedia
Menu

© 2025 NumberPedia

Composite Number

1686

1686 is a even composite number that follows 1685 and precedes 1687. It is composed of 8 distinct factors: 1, 2, 3, 6, 281, 562, 843, 1686. Its prime factorization can be written as 2 × 3 × 281. 1686 is classified as a abundant number based on the sum of its proper divisors. In computer science, 1686 is represented as 11010010110 in binary and 696 in hexadecimal. Historically, it is written as MDCLXXXVI in Roman numerals.

Roman Numeral
MDCLXXXVI
LatinClassic
Binary
11010010110
Base 2
Hexadecimal
696
Base 16

Factor Analysis

8 Factors

Properties

ParityEven
Perfect SquareNo
Perfect CubeNo
Digit Count4
Digit Sum21
Digital Root3
Sum of Factors3384
Aliquot Sum1698
ClassificationAbundant
Prime Factors3
SequencesComposite numbers, Abundant numbers
Prime Factorization

The prime factorization (2 × 3 × 281) reveals 3 prime building blocks.

Canonical form
2 × 3 × 281
23281
Divisibility Insights
  • Divisible by 2

    1686 ends in 6, so it is even.

  • Divisible by 3

    The digit sum 21 is a multiple of 3.

  • Divisible by 4

    The last two digits 86 are not divisible by 4.

  • Divisible by 5

    1686 does not end in 0 or 5.

  • Divisible by 6

    It meets the tests for both 2 and 3, so it is divisible by 6.

  • Divisible by 9

    The digit sum 21 is not a multiple of 9.

  • Divisible by 10

    1686 does not end in 0.

  • Divisible by 11

    The alternating digit sum -3 is not a multiple of 11.

Sequence Membership

Abundant classification and digit analytics place 1686 within several notable number theory sequences:

Composite numbersAbundant numbers
Advertisement

Deep dive

How 1686 breaks down

1686 carries 8 distinct factors and a digit signature of 21 (3 as the digital root). The abundant classification indicates that its proper divisors sum to 1698, which exceeds the number, offering a quick glimpse into its abundance profile.

Numeral conversions provide additional context: the binary form 11010010110 supports bitwise reasoning, hexadecimal 696 aligns with computing notation, and the Roman numeral MDCLXXXVI keeps the encyclopedic tradition alive. These attributes make 1686 useful for math olympiad problems, puzzle design, and code challenges alike.

Context

Where 1686 shows up

Engineers lean on the divisibility profile when sizing circuits, mod designers use neighboring values (16811691) to tune search ranges, and educators feature 1686 in worksheets about factor trees. Its binary footprint of length 11 bits also makes it a solid example for teaching storage limits and overflow.

Beyond STEM, the classification and sequence tags (Composite numbers, Abundant numbers) help historians, numerologists, and trivia writers tie 1686 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 1686

Is 1686 a prime number?

1686 is composite with 8 total factors and the prime factorization 2 × 3 × 281.

What is the prime factorization of 1686?

It breaks down as 2 × 3 × 281, multiplying the primes 2 × 3 × 281.

How is 1686 represented in binary and hexadecimal?

1686 converts to 11010010110 in binary and 696 in hexadecimal, which are helpful for computer science applications.

Is 1686 a perfect square, cube, or triangular number?

1686 is not a perfect square, is not a perfect cube, and is not triangular.

What are the digit sum and digital root of 1686?

The digits sum to 21, producing a digital root of 3. These tests power divisibility shortcuts for 3 and 9.