239
+239 is the international calling code for São Tomé and Príncipe.
- Odd
- Prime
Where 239 fits
Why 239 is special
São Tomé is one of the smallest African states by population and sits almost exactly on the equator and the prime meridian.
Same number, different meanings
How 239 is understood across different contexts — never implying one meaning because of another.
- Mathematics
São Tomé is one of the smallest African states by population and sits almost exactly on the equator and the prime meridian.
- Science
Plutonium-239 is produced by neutron capture in uranium-238 rather than mined. Its 24,100-year half-life and fissile properties make reactor-grade separation a proliferation concern.
- Geography
+239 reaches São Tomé and Príncipe, whose territory lies close to the intersection of the equator and the prime meridian — the nominal zero point of the coordinate system.
239 is part of
Factors & digit properties
- Divisors (2)
- 1, 239
- Prime factorisation
- 239
- Digit sum
- 14
- Digital root
- 5
Representations
- Decimal
- 239
- Scientific notation
- 2.390 × 10^2
Roman numerals
C C X X X I X
CCXXXIX uses the subtractive pair IX: one before ten — ten minus one.
Binary
1 1 1 0 1 1 1 1
1 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 1 × 4 + 1 × 2 + 1 × 1 = 239
Octal
3 5 7
3 × 64 + 5 × 8 + 7 × 1 = 239
Hexadecimal
e f
e × 16 + f × 1 = 239
Read as powers of two: 128 + 64 + 32 + 8 + 4 + 2 + 1 = 239.
In historical numeral systems
Egyptian
2 coils of rope, 3 hobbles, 9 strokes
2 × 100 + 3 × 10 + 9 × 1 = 239. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 vertical wedges (sixties place), 5 corner wedges + 9 vertical wedges (units place)
3 × 60 + 59 = 239. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
sigma, then lambda, then theta, marked as a numeral
sigma-lambda-theta + keraia
sigma + lambda + theta written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
resh, then lamed, then tet
resh-lamed-tet
resh (200) + lamed (30) + tet (9) = 239, written in descending order.
Maya
2 bars + 1 dot (upper, twenties place) over 3 bars + 4 dots (lower, units place)
11 × 20 + 19 = 239. 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
- Happy number
- Sophie Germain prime
- Twin prime
Related numbers & connections
Cape Verde and São Tomé and Príncipe are both Atlantic archipelagos that were uninhabited before Portuguese settlement, so their creole cultures formed entirely from that encounter.
View 238 →Other connections
- is associated with238
why?
Strength 0.50, confidence "high".
Science
Plutonium-239 is produced by neutron capture in uranium-238 rather than mined. Its 24,100-year half-life and fissile properties make reactor-grade separation a proliferation concern.
DocumentedScienceGeography: GlobalPeriod: 1941–
Geography
+239 reaches São Tomé and Príncipe, whose territory lies close to the intersection of the equator and the prime meridian — the nominal zero point of the coordinate system.
DocumentedGeographyGeography: São Tomé and Príncipe
Common questions
Is 239 a prime number?
Yes, 239 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 239?
The factors of 239 are 1, 239.
What is 239 in Roman numerals?
239 in Roman numerals is CCXXXIX. IX is subtractive: one before ten — ten minus one. Written additively it would be CCXXXVIIII, 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: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026