169
169 is the copyright sign.
Where 169 fits
Why 169 is special
The Berne Convention removed the requirement to mark a work at all, so the symbol is now a convention rather than a condition of protection.
169 is part of
Factors & digit properties
- Divisors (3)
- 1, 13, 169
- Prime factorisation
- 13^2
- Digit sum
- 16
- Digital root
- 7
Representations
- Decimal
- 169
- Scientific notation
- 1.690 × 10^2
Roman numerals
C L X I X
CLXIX uses the subtractive pair IX: one before ten — ten minus one.
Binary
1 0 1 0 1 0 0 1
1 × 128 + 0 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 169
Octal
2 5 1
2 × 64 + 5 × 8 + 1 × 1 = 169
Hexadecimal
a 9
a × 16 + 9 × 1 = 169
Read as powers of two: 128 + 32 + 8 + 1 = 169.
In historical numeral systems
Egyptian
1 coil of rope, 6 hobbles, 9 strokes
1 × 100 + 6 × 10 + 9 × 1 = 169. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
2 vertical wedges (sixties place), 4 corner wedges + 9 vertical wedges (units place)
2 × 60 + 49 = 169. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
rho, then xi, then theta, marked as a numeral
rho-xi-theta + keraia
rho + xi + theta written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
qof, then samekh, then tet
qof-samekh-tet
qof (100) + samekh (60) + tet (9) = 169, written in descending order.
Maya
1 bar + 3 dots (upper, twenties place) over 1 bar + 4 dots (lower, units place)
8 × 20 + 9 = 169. Places stack vertically with the smallest at the bottom, so the upper group is worth twenty times the lower.
Systems that simply cannot reach this value are left out. Where a script needs a font most readers do not have, the reading is given instead of the glyphs — see number systems for each system in full.
Other mathematical patterns
- Deficient number
- Powerful number
- Semiprime
- Lucky number (mathematical sieve)
Related numbers & connections
Both are legal notices reduced to single characters, and neither creates the right it refers to.
View 174 →Copyright arises on creation and registration is required for the registered mark, which is why only one notice is optional.
View 174 →Technology & computing
U+00A9 COPYRIGHT SIGN indicates a claim of copyright. Under the Berne Convention protection arises on creation without formality, so the notice is informative rather than constitutive in signatory states.
DocumentedTechnology & computingGeography: International — Unicode ConsortiumPeriod: 1991–
Common questions
Is 169 a prime number?
No, 169 is not prime.
What are the factors of 169?
The factors of 169 are 1, 13, 169.
What is 169 in Roman numerals?
169 in Roman numerals is CLXIX. IX is subtractive: one before ten — ten minus one. Written additively it would be CLXVIIII, which Roman inscriptions used freely — the strict subtractive form is a later convention.
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: 15 July 2026