245
+245 is the international calling code for Guinea-Bissau.
- Odd
- Composite
Where 245 fits
Why 245 is special
Guinea-Bissau is one of three West African countries with Guinea in the name, distinguished by capital, former coloniser and calling code.
Factors & digit properties
- Divisors (6)
- 1, 5, 7, 35, 49, 245
- Prime factorisation
- 5 × 7^2
- Digit sum
- 11
- Digital root
- 2
Representations
- Decimal
- 245
- Scientific notation
- 2.450 × 10^2
Roman numerals
C C X L V
CCXLV uses the subtractive pair XL: ten before fifty — fifty minus ten.
Binary
1 1 1 1 0 1 0 1
1 × 128 + 1 × 64 + 1 × 32 + 1 × 16 + 0 × 8 + 1 × 4 + 0 × 2 + 1 × 1 = 245
Octal
3 6 5
3 × 64 + 6 × 8 + 5 × 1 = 245
Hexadecimal
f 5
f × 16 + 5 × 1 = 245
Read as powers of two: 128 + 64 + 32 + 16 + 4 + 1 = 245.
In historical numeral systems
Egyptian
2 coils of rope, 4 hobbles, 5 strokes
2 × 100 + 4 × 10 + 5 × 1 = 245. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
4 vertical wedges (sixties place), 5 vertical wedges (units place)
4 × 60 + 5 = 245. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
sigma, then mu, then epsilon, marked as a numeral
sigma-mu-epsilon + keraia
sigma + mu + epsilon 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 mem, then he
resh-mem-he
resh (200) + mem (40) + he (5) = 245, written in descending order.
Maya
2 bars + 2 dots (upper, twenties place) over 1 bar (lower, units place)
12 × 20 + 5 = 245. 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
Related numbers & connections
Guinea and Guinea-Bissau are two of the three West African states carrying Guinea in the name, distinguished in practice by their codes and former colonisers.
View 224 →Nearby in a sequence
- is adjacent to224
why?
Strength 0.50, confidence "high".
Geography
+245 reaches Guinea-Bissau. Guinea, Guinea-Bissau and Equatorial Guinea are separate countries with separate codes, and the shared name causes routine confusion in shipping and correspondence.
DocumentedGeographyGeography: Guinea-Bissau
Common questions
Is 245 a prime number?
No, 245 is not prime.
What are the factors of 245?
The factors of 245 are 1, 5, 7, 35, 49, 245.
What is 245 in Roman numerals?
245 in Roman numerals is CCXLV. XL is subtractive: ten before fifty — fifty minus ten. Written additively it would be CCXXXXV, 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