155
155 is a odd composite number that follows 154 and precedes 156. It is composed of 4 distinct factors: 1, 5, 31, 155. Its prime factorization can be written as 5 × 31. 155 is classified as a deficient number based on the sum of its proper divisors. In computer science, 155 is represented as 10011011 in binary and 9B in hexadecimal. Historically, it is written as CLV in Roman numerals.
Factor Analysis
4 FactorsProperties
The prime factorization (5 × 31) reveals 2 prime building blocks.
Divisible by 2
155 ends in 5, so it is odd.
Divisible by 3
The digit sum 11 is not a multiple of 3.
Divisible by 4
The last two digits 55 are not divisible by 4.
Divisible by 5
155 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 11 is not a multiple of 9.
Divisible by 10
155 does not end in 0.
Divisible by 11
The alternating digit sum 1 is not a multiple of 11.
Deficient classification and digit analytics place 155 within several notable number theory sequences:
Timeline
Deep dive
How 155 breaks down
155 carries 4 distinct factors and a digit signature of 11 (2 as the digital root). The deficient classification indicates that its proper divisors sum to 37, which stays below the number, offering a quick glimpse into its abundance profile.
Numeral conversions provide additional context: the binary form 10011011 supports bitwise reasoning, hexadecimal 9B aligns with computing notation, and the Roman numeral CLV keeps the encyclopedic tradition alive. These attributes make 155 useful for math olympiad problems, puzzle design, and code challenges alike.
Context
Where 155 shows up
Engineers lean on the divisibility profile when sizing circuits, mod designers use neighboring values (150–160) to tune search ranges, and educators feature 155 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 155 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 155
Is 155 a prime number?
155 is composite with 4 total factors and the prime factorization 5 × 31.
What is the prime factorization of 155?
It breaks down as 5 × 31, multiplying the primes 5 × 31.
How is 155 represented in binary and hexadecimal?
155 converts to 10011011 in binary and 9B in hexadecimal, which are helpful for computer science applications.
Is 155 a perfect square, cube, or triangular number?
155 is not a perfect square, is not a perfect cube, and is not triangular.
What are the digit sum and digital root of 155?
The digits sum to 11, producing a digital root of 2. These tests power divisibility shortcuts for 3 and 9.