2178
2,178 multiplied by 4 gives its own digits reversed.
- Even
- Composite
Where 2178 fits
Why 2178 is special
It is the smallest number with that property in base ten, and the only other four-digit example is 8,712 with a multiplier of 4. Such reverse-multiple numbers are rare and follow a strict pattern.
Factors & digit properties
- Divisors (18)
- 1, 2, 3, 6, 9, 11, 18, 22, 33, 66, 99, 121, 198, 242, 363, 726, 1089, 2178
- Prime factorisation
- 2 × 3^2 × 11^2
- Digit sum
- 18
- Digital root
- 9
Representations
- Decimal
- 2178
- Scientific notation
- 2.178 × 10^3
Roman numerals
M M C L X X V I I I
Binary
1 0 0 0 1 0 0 0 0 0 1 0
1 × 2,048 + 0 × 1,024 + 0 × 512 + 0 × 256 + 1 × 128 + 0 × 64 + 0 × 32 + 0 × 16 + 0 × 8 + 0 × 4 + 1 × 2 + 0 × 1 = 2,178
Octal
4 2 0 2
4 × 512 + 2 × 64 + 0 × 8 + 2 × 1 = 2,178
Hexadecimal
8 8 2
8 × 256 + 8 × 16 + 2 × 1 = 2,178
Read as powers of two: 2,048 + 128 + 2 = 2,178.
In historical numeral systems
Egyptian
2 lotuses, 1 coil of rope, 7 hobbles, 8 strokes
2 × 1,000 + 1 × 100 + 7 × 10 + 8 × 1 = 2,178. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
3 corner wedges + 6 vertical wedges (sixties place), 1 corner wedge + 8 vertical wedges (units place)
36 × 60 + 18 = 2178. 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
- Abundant number
- Harshad (Niven) number
Mathematics
Multiplying 2,178 by four produces 8,712, which is the same digits in reverse order. Only two four-digit numbers in base ten do this, which is why the pair turns up in puzzle collections and why finding a third by hand is impossible — there is not one.
DocumentedMathematics
Common questions
Is 2178 a prime number?
No, 2178 is not prime.
What are the factors of 2178?
The factors of 2178 are 1, 2, 3, 6, 9, 11, 18, 22, 33, 66, 99, 121, 198, 242, 363, 726, 1089, 2178.
What is 2178 in Roman numerals?
2178 in Roman numerals is MMCLXXVIII.
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