3475
The Moon is about 3,475 km across.
- Odd
- Composite
Where 3475 fits
Why 3475 is special
It is slightly wider than Australia. The Moon and Sun appear almost exactly the same size from Earth — the Sun is about 400 times wider and about 400 times further away — which is a coincidence, and the reason total solar eclipses look the way they do.
3475 connects to:
- 1738 — is a multiple of
- numbers in space — appears in
Same number, different meanings
How 3475 is understood across different contexts — never implying one meaning because of another.
- Mathematics
It is slightly wider than Australia. The Moon and Sun appear almost exactly the same size from Earth — the Sun is about 400 times wider and about 400 times further away — which is a coincidence, and the reason total solar eclipses look the way they do.
- History
The Moon's size was worked out in antiquity from the shape of Earth's shadow crossing it during a lunar eclipse: the curvature of the shadow's edge gives the ratio of the two bodies. Aristarchus and later Hipparchus obtained figures within a moderate fraction of the modern one, using geometry and patience alone. The distance and the diameter came together, because either one fixes the other once the Moon's apparent width is known.
- Science
The diameter of the Moon is 3475 kilometres (the Earth-Moon system). About a quarter of the Earth's, which is unusually large for a moon relative to its planet.
3475 is part of
Factors & digit properties
- Divisors (6)
- 1, 5, 25, 139, 695, 3475
- Prime factorisation
- 5^2 × 139
- Digit sum
- 19
- Digital root
- 1
Representations
- Decimal
- 3475
- Scientific notation
- 3.475 × 10^3
Roman numerals
M M M C D L X X V
MMMCDLXXV uses the subtractive pair CD: a hundred before five hundred — five hundred minus a hundred.
Binary
1 1 0 1 1 0 0 1 0 0 1 1
1 × 2,048 + 1 × 1,024 + 0 × 512 + 1 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 0 × 8 + 0 × 4 + 1 × 2 + 1 × 1 = 3,475
Octal
6 6 2 3
6 × 512 + 6 × 64 + 2 × 8 + 3 × 1 = 3,475
Hexadecimal
d 9 3
d × 256 + 9 × 16 + 3 × 1 = 3,475
Read as powers of two: 2,048 + 1,024 + 256 + 128 + 16 + 2 + 1 = 3,475.
In historical numeral systems
Egyptian
3 lotuses, 4 coils of rope, 7 hobbles, 5 strokes
3 × 1,000 + 4 × 100 + 7 × 10 + 5 × 1 = 3,475. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
5 corner wedges + 7 vertical wedges (sixties place), 5 corner wedges + 5 vertical wedges (units place)
57 × 60 + 55 = 3475. Places are separated by a space on the tablet, with the higher place written first.
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
The Moon's diameter is twice its radius, and both are about a quarter of Earth's — exceptionally large for a moon relative to its planet.
View 1738 →3475 appears in Numbers in space, the topic covering numbers that carry a documented astronomy fact.
Mathematically related
- is a multiple of1738
why?
Strength 0.50, confidence "high".
Numbers Around Us
- appears inSpace and astronomy
why?
Strength 0.50, confidence "high".
History
The Moon's size was worked out in antiquity from the shape of Earth's shadow crossing it during a lunar eclipse: the curvature of the shadow's edge gives the ratio of the two bodies. Aristarchus and later Hipparchus obtained figures within a moderate fraction of the modern one, using geometry and patience alone. The distance and the diameter came together, because either one fixes the other once the Moon's apparent width is known.
DocumentedHistoryPeriod: 3rd–2nd century BCE
Science
The diameter of the Moon is 3475 kilometres (the Earth-Moon system). About a quarter of the Earth's, which is unusually large for a moon relative to its planet.
DocumentedScienceGeography: the Earth-Moon systemThe Moon is about 3,475 km across — slightly wider than Australia. The Sun is roughly 400 times wider and roughly 400 times further away, so the two appear almost identical in size from Earth. Nothing requires that; it is why total solar eclipses look as they do.
DocumentedScience
Common questions
Is 3475 a prime number?
No, 3475 is not prime.
What are the factors of 3475?
The factors of 3475 are 1, 5, 25, 139, 695, 3475.
What is 3475 in Roman numerals?
3475 in Roman numerals is MMMCDLXXV. CD is subtractive: a hundred before five hundred — five hundred minus a hundred. Written additively it would be MMMCCCCLXXV, 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: 3 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026