225
225 is a perfect square (15²) with an unusually rich factor structure for its size.
Where 225 fits
Why 225 is special
225 is 15² — and since 15 = 3 × 5, that makes 225 the square of a product of the first two odd primes, giving it nine factors (more than most numbers near its size), and qualifying it as both a 'powerful' number (every prime factor's exponent is at least 2) and a Harshad number (divisible by its own digit sum, 2+2+5=9).
225 is part of
Factors & digit properties
- Divisors (9)
- 1, 3, 5, 9, 15, 25, 45, 75, 225
- Prime factorisation
- 3^2 × 5^2
- Digit sum
- 9
- Digital root
- 9
Representations
- Decimal
- 225
- Scientific notation
- 2.250 × 10^2
Roman numerals
C C X X V
Binary
1 1 1 0 0 0 0 1
1 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 225
Octal
3 4 1
3 × 64 + 4 × 8 + 1 × 1 = 225
Hexadecimal
e 1
e × 16 + 1 × 1 = 225
Read as powers of two: 128 + 64 + 32 + 1 = 225.
In historical numeral systems
Egyptian
2 coils of rope, 2 hobbles, 5 strokes
2 × 100 + 2 × 10 + 5 × 1 = 225. 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), 4 corner wedges + 5 vertical wedges (units place)
3 × 60 + 45 = 225. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
sigma, then kappa, then epsilon, marked as a numeral
sigma-kappa-epsilon + keraia
sigma + kappa + 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 kaf, then he
resh-kaf-he
resh (200) + kaf (20) + he (5) = 225, written in descending order.
Maya
2 bars + 1 dot (upper, twenties place) over 1 bar (lower, units place)
11 × 20 + 5 = 225. 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
- Harshad (Niven) number
Related numbers & connections
9 is a factor of 225 (9 × 25 = 225).
View 9 →Tilting let the Pendolino take a Victorian alignment at speed, where the earlier fleet needed the route straightened.
View 390 →Symbolic meaning
In modern numerology, 225 is said to combine the meanings of 2 (balance, partnership) and 5 (change), and is sometimes described as a 'manifestation' or 'angel number'. This is a belief-system interpretation, not an empirical claim.
Belief / interpretationSymbolic meaningPresented as belief or tradition, not as an established fact.
Common questions
Why is 225 special?
225 is a perfect square — 15² — and since 15 = 3 × 5, that gives 225 nine factors in total, more than most numbers near its size. It also qualifies as a 'powerful' number and a Harshad number (divisible by its own digit sum, 9).
What are the factors of 225?
1, 3, 5, 9, 15, 25, 45, 75 and 225 — nine factors in total, reflecting its 3²×5² structure.
Is 225 a prime number?
No, 225 is not prime.
What is 225 in Roman numerals?
225 in Roman numerals is CCXXV.
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