643
643 is a odd prime number that follows 642 and precedes 644. As a prime number, 643 is only divisible by 1 and itself. It holds a unique position in the sequence of integers. Its prime factorization is simply 643. 643 is classified as a deficient number based on the sum of its proper divisors. In computer science, 643 is represented as 1010000011 in binary and 283 in hexadecimal. Historically, it is written as DCXLIII in Roman numerals.
Factor Analysis
2 FactorsProperties
643 is prime, so its only factors are 1 and 643.
Divisible by 2
643 ends in 3, so it is odd.
Divisible by 3
The digit sum 13 is not a multiple of 3.
Divisible by 4
The last two digits 43 are not divisible by 4.
Divisible by 5
643 does not end in 0 or 5.
Divisible by 6
A number must be divisible by 2 and 3 to pass the 6-test.
Divisible by 9
The digit sum 13 is not a multiple of 9.
Divisible by 10
643 does not end in 0.
Divisible by 11
The alternating digit sum 5 is not a multiple of 11.
Deficient classification and digit analytics place 643 within several notable number theory sequences:
Timeline
Deep dive
How 643 breaks down
643 carries 2 distinct factors and a digit signature of 13 (4 as the digital root). The deficient classification indicates that its proper divisors sum to 1, which stays below the number, offering a quick glimpse into its abundance profile.
Numeral conversions provide additional context: the binary form 1010000011 supports bitwise reasoning, hexadecimal 283 aligns with computing notation, and the Roman numeral DCXLIII keeps the encyclopedic tradition alive. These attributes make 643 useful for math olympiad problems, puzzle design, and code challenges alike.
Context
Where 643 shows up
Engineers lean on the divisibility profile when sizing circuits, mod designers use neighboring values (638–648) to tune search ranges, and educators feature 643 in worksheets about prime identification. Its binary footprint of length 10 bits also makes it a solid example for teaching storage limits and overflow.
Beyond STEM, the classification and sequence tags (Prime numbers, Deficient numbers) help historians, numerologists, and trivia writers tie 643 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 643
Is 643 a prime number?
643 is prime, meaning it is only divisible by 1 and itself.
What is the prime factorization of 643?
643 is already prime, so the factorization is simply 643.
How is 643 represented in binary and hexadecimal?
643 converts to 1010000011 in binary and 283 in hexadecimal, which are helpful for computer science applications.
Is 643 a perfect square, cube, or triangular number?
643 is not a perfect square, is not a perfect cube, and is not triangular.
What are the digit sum and digital root of 643?
The digits sum to 13, producing a digital root of 4. These tests power divisibility shortcuts for 3 and 9.