490
490 BC is the year of the Battle of Marathon.
- Even
- Composite
Where 490 fits
Why 490 is special
An Athenian force defeated a much larger Persian army. The modern marathon distance commemorates a messenger's run that Herodotus, writing closest to the events, does not mention.
490 is part of
Factors & digit properties
- Divisors (12)
- 1, 2, 5, 7, 10, 14, 35, 49, 70, 98, 245, 490
- Prime factorisation
- 2 × 5 × 7^2
- Digit sum
- 13
- Digital root
- 4
Representations
- Decimal
- 490
- Scientific notation
- 4.900 × 10^2
Roman numerals
C D X C
CDXC uses the subtractive pair XC: ten before a hundred — a hundred minus ten.
Binary
1 1 1 1 0 1 0 1 0
1 × 256 + 1 × 128 + 1 × 64 + 1 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 1 × 2 + 0 × 1 = 490
Octal
7 5 2
7 × 64 + 5 × 8 + 2 × 1 = 490
Hexadecimal
1 e a
1 × 256 + e × 16 + a × 1 = 490
Read as powers of two: 256 + 128 + 64 + 32 + 8 + 2 = 490.
In historical numeral systems
Egyptian
4 coils of rope, 9 hobbles
4 × 100 + 9 × 10 = 490. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
8 vertical wedges (sixties place), 1 corner wedge (units place)
8 × 60 + 10 = 490. Places are separated by a space on the tablet, with the higher place written first.
Greek (Ionic)
upsilon, then koppa, marked as a numeral
upsilon-koppa + keraia
upsilon + koppa written in descending order and added — the letters carry their values wherever they stand, so this is addition, not place value.
Hebrew numerals
tav, then tsadi
tav-tsadi
tav (400) + tsadi (90) = 490, written in descending order.
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
- Abundant number
- Happy number
Related numbers & connections
Marathon in 490 BC and Thermopylae and Salamis ten years later are the two Persian invasions of Greece. The first was repelled by Athens alone and the second required a Greek coalition.
View 480 →Numbers Around Us
- appears alongside480
why?
Strength 0.50, confidence "high".
History
Marathon in 490 BC is real; the runner who died delivering news of it appears only in accounts written centuries later. Herodotus describes a different and much longer run, by a professional courier who survived.
DocumentedHistoryGeography: GreecePeriod: 490 BC
Common questions
Is 490 a prime number?
No, 490 is not prime.
What are the factors of 490?
The factors of 490 are 1, 2, 5, 7, 10, 14, 35, 49, 70, 98, 245, 490.
What is 490 in Roman numerals?
490 in Roman numerals is CDXC. XC is subtractive: ten before a hundred — a hundred minus ten. Written additively it would be CCCCLXXXX, 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