640
640 is a even composite number that follows 639 and precedes 641. It is composed of 16 distinct factors: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320, 640. Its prime factorization can be written as 2^7 × 5. 640 is classified as a abundant number based on the sum of its proper divisors. In computer science, 640 is represented as 1010000000 in binary and 280 in hexadecimal. Historically, it is written as DCXL in Roman numerals.
Factor Analysis
16 FactorsProperties
The prime factorization (2^7 × 5) reveals 8 prime building blocks.
Divisible by 2
640 ends in 0, so it is even.
Divisible by 3
The digit sum 10 is not a multiple of 3.
Divisible by 4
The last two digits 40 form a multiple of 4.
Divisible by 5
640 ends in 0, 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 10 is not a multiple of 9.
Divisible by 10
640 ends in 0.
Divisible by 11
The alternating digit sum 2 is not a multiple of 11.
Abundant classification and digit analytics place 640 within several notable number theory sequences:
Timeline
Deep dive
How 640 breaks down
640 carries 16 distinct factors and a digit signature of 10 (1 as the digital root). The abundant classification indicates that its proper divisors sum to 890, which exceeds the number, offering a quick glimpse into its abundance profile.
Numeral conversions provide additional context: the binary form 1010000000 supports bitwise reasoning, hexadecimal 280 aligns with computing notation, and the Roman numeral DCXL keeps the encyclopedic tradition alive. These attributes make 640 useful for math olympiad problems, puzzle design, and code challenges alike.
Context
Where 640 shows up
Engineers lean on the divisibility profile when sizing circuits, mod designers use neighboring values (635–645) to tune search ranges, and educators feature 640 in worksheets about factor trees. 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 (Composite numbers, Abundant numbers) help historians, numerologists, and trivia writers tie 640 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 640
Is 640 a prime number?
640 is composite with 16 total factors and the prime factorization 2^7 × 5.
What is the prime factorization of 640?
It breaks down as 2^7 × 5, multiplying the primes 2 × 2 × 2 × 2 × 2 × 2 × 2 × 5.
How is 640 represented in binary and hexadecimal?
640 converts to 1010000000 in binary and 280 in hexadecimal, which are helpful for computer science applications.
Is 640 a perfect square, cube, or triangular number?
640 is not a perfect square, is not a perfect cube, and is not triangular.
What are the digit sum and digital root of 640?
The digits sum to 10, producing a digital root of 1. These tests power divisibility shortcuts for 3 and 9.