840
840 is a highly composite number with 32 divisors.
- Even
- Composite
Where 840 fits
Why 840 is special
Numbers like this divide evenly in many ways, which is why they are chosen for things that must be split repeatedly — 60 seconds, 360 degrees, 12 inches. 840 is the smallest number divisible by all of 1 to 8.
Factors & digit properties
- Divisors (32)
- 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 15, 20, 21, 24, 28, 30, 35, 40, 42, 56, 60, 70, 84, 105, 120, 140, 168, 210, 280, 420, 840
- Prime factorisation
- 2^3 × 3 × 5 × 7
- Digit sum
- 12
- Digital root
- 3
Representations
- Decimal
- 840
- Binary
- 1101001000
- Octal
- 1510
- Hexadecimal
- 348
- Roman numeral
- DCCCXL
- Scientific notation
- 8.400 × 10^2
Other mathematical patterns
- Abundant number
- Highly composite number
- Harshad (Niven) number
Mathematics
840 is the smallest number divisible by each of 1 to 8, which is why it appears wherever a quantity must be split many ways without remainder. It is the same reasoning that put 60 minutes in an hour and 360 degrees in a circle, carried further.
DocumentedMathematics
Common questions
Is 840 a prime number?
No, 840 is not prime.
What are the factors of 840?
The factors of 840 are 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 15, 20, 21, 24, 28, 30, 35, 40, 42, 56, 60, 70, 84, 105, 120, 140, 168, 210, 280, 420, 840.
What is 840 in Roman numerals?
840 in Roman numerals is DCCCXL.
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