233
233 is a Fibonacci number and one of the few that is also prime.
Where 233 fits
Why 233 is special
Fibonacci primes are rare and it is still unknown whether there are infinitely many — an open problem about a sequence otherwise taught to children. 233 is the thirteenth Fibonacci number, and 13 being prime is a necessary condition for the term to be prime.
233 is part of
Factors & digit properties
- Divisors (2)
- 1, 233
- Prime factorisation
- 233
- Digit sum
- 8
- Digital root
- 8
Representations
- Decimal
- 233
- Scientific notation
- 2.330 × 10^2
Roman numerals
C C X X X I I I
Binary
1 1 1 0 1 0 0 1
1 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 233
Octal
3 5 1
3 × 64 + 5 × 8 + 1 × 1 = 233
Hexadecimal
e 9
e × 16 + 9 × 1 = 233
Read as powers of two: 128 + 64 + 32 + 8 + 1 = 233.
In historical numeral systems
Egyptian
2 coils of rope, 3 hobbles, 3 strokes
2 × 100 + 3 × 10 + 3 × 1 = 233. 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 + 3 vertical wedges (units place)
3 × 60 + 53 = 233. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
sigma, then lambda, then gamma, marked as a numeral
sigma-lambda-gamma + keraia
sigma + lambda + gamma 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 gimel
resh-lamed-gimel
resh (200) + lamed (30) + gimel (3) = 233, written in descending order.
Maya
2 bars + 1 dot (upper, twenties place) over 2 bars + 3 dots (lower, units place)
11 × 20 + 13 = 233. 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
- Sophie Germain prime
Related numbers & connections
Both are Fibonacci primes, four places apart in the sequence. 1,597 divided by 233 is close to the golden ratio raised to the fourth power, which is what Fibonacci ratios converge on.
View 1597 →233 is the thirteenth Fibonacci number and one of the few that is also prime.
Mathematically related
- has multiple1597
why?
Strength 0.50, confidence "high".
Numbers Around Us
- appears inFibonacci sequence
why?
Strength 0.50, confidence "high".
Mathematics
233 is the thirteenth Fibonacci number and also prime. Fibonacci primes are scarce, and whether infinitely many exist is unresolved — an open question about a sequence otherwise simple enough to teach to children.
DocumentedMathematics
Common questions
Is 233 a prime number?
Yes, 233 is prime — it has exactly two positive divisors: 1 and itself.
What are the factors of 233?
The factors of 233 are 1, 233.
What is 233 in Roman numerals?
233 in Roman numerals is CCXXXIII.
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