148
A5 paper is 148 mm wide.
- Even
- Composite
Where 148 fits
Why 148 is special
Halving A4 across its long side gives A5, and the width of A5 is half A4's height. That relationship holds all the way up and down the series because every sheet shares the same square-root-of-two proportion.
Factors & digit properties
- Divisors (6)
- 1, 2, 4, 37, 74, 148
- Prime factorisation
- 2^2 × 37
- Digit sum
- 13
- Digital root
- 4
Representations
- Decimal
- 148
- Binary
- 10010100
- Octal
- 224
- Hexadecimal
- 94
- Roman numeral
- CXLVIII
- Scientific notation
- 1.480 × 10^2
Other mathematical patterns
- Deficient number
Related numbers & connections
A5 is 148 by 210 mm and A4 is 210 by 297: the width of each size is the height of the next one down. That only works because every sheet shares the square-root-of-two ratio.
View 210 →Mathematically related
- has factor210
why?
Strength 0.50, confidence "high".
Everyday life
A5 is 148 by 210 mm — exactly half an A4 sheet, and the same proportions. The width of each size is the height of the next one down, which is only possible because the ratio is the square root of two.
DocumentedEveryday lifeGeography: International outside North America
Common questions
Is 148 a prime number?
No, 148 is not prime.
What are the factors of 148?
The factors of 148 are 1, 2, 4, 37, 74, 148.
What is 148 in Roman numerals?
148 in Roman numerals is CXLVIII.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 1 reviewer-confirmed record, sourced and reviewed before publication.
Last reviewed: 3 August 2026