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
- Binary
- 100010000010
- Octal
- 4202
- Hexadecimal
- 882
- Roman numeral
- MMCLXXVIII
- Scientific notation
- 2.178 × 10^3
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: 3 August 2026