660
Aluminium melts at about 660 degrees Celsius.
- Even
- Composite
Where 660 fits
Why 660 is special
Aluminium is the most abundant metal in the Earth's crust and was more valuable than gold in the 1850s, because separating it from its ore requires electricity rather than heat. Napoleon III reputedly reserved aluminium cutlery for his most honoured guests.
Factors & digit properties
- Divisors (24)
- 1, 2, 3, 4, 5, 6, 10, 11, 12, 15, 20, 22, 30, 33, 44, 55, 60, 66, 110, 132, 165, 220, 330, 660
- Prime factorisation
- 2^2 × 3 × 5 × 11
- Digit sum
- 12
- Digital root
- 3
Representations
- Decimal
- 660
- Scientific notation
- 6.600 × 10^2
Roman numerals
D C L X
Binary
1 0 1 0 0 1 0 1 0 0
1 × 512 + 0 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 0 × 8 + 1 × 4 + 0 × 2 + 0 × 1 = 660
Octal
1 2 2 4
1 × 512 + 2 × 64 + 2 × 8 + 4 × 1 = 660
Hexadecimal
2 9 4
2 × 256 + 9 × 16 + 4 × 1 = 660
Read as powers of two: 512 + 128 + 16 + 4 = 660.
In historical numeral systems
Egyptian
6 coils of rope, 6 hobbles
6 × 100 + 6 × 10 = 660. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
1 corner wedge + 1 vertical wedge (sixties place), empty units place
11 × 60 + 0 = 660. Places are separated by a space on the tablet, with the higher place written first. The second place is empty, and this is precisely the case the early system could not write unambiguously — the same wedges alone would also read as 1.
Greek (Ionic)
chi, then xi, marked as a numeral
chi-xi + keraia
chi + xi 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 resh, then samekh
tav-resh-samekh
tav (400) + resh (200) + samekh (60) = 660, 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
- Harshad (Niven) number
Related numbers & connections
Aluminium melts at about 660 degrees and iron at 1,538, yet aluminium was a precious metal into the 1880s. Its ore resists heat alone and needs electricity, so melting point and availability came apart completely.
View 1538 →Other connections
- contrasts with1538
why?
Strength 0.50, confidence "high".
Science
The melting point of aluminium is 660 degrees Celsius (worldwide, at standard pressure). Low enough to cast in a workshop furnace, and low enough to matter in a fire: an aluminium ladder or engine block fails long before a steel one.
DocumentedScienceGeography: worldwide, at standard pressureAluminium is the commonest metal in the crust and was a precious material until electrolytic extraction arrived in 1886. Its ore cannot be reduced by heat alone, which is why abundance and availability diverged so sharply.
DocumentedScience
Common questions
Is 660 a prime number?
No, 660 is not prime.
What are the factors of 660?
The factors of 660 are 1, 2, 3, 4, 5, 6, 10, 11, 12, 15, 20, 22, 30, 33, 44, 55, 60, 66, 110, 132, 165, 220, 330, 660.
What is 660 in Roman numerals?
660 in Roman numerals is DCLX.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026