840 in words
840
eight hundred and forty
840 is written eight hundred and forty.
Ways to write it
- As an ordinal
- eight hundred and fortieth
- Roman numeral
- DCCCXL
- Expanded form
- 800 + 40
Place value
| Place | Digit | Value |
|---|---|---|
| hundreds | 8 | 800 |
| tens | 4 | 40 |
| ones | 0 | 0 |
Number facts
- Even or odd
- Even
- Prime or composite
- Composite
- Factors
- 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 and 840 (32 factors)
- First 10 multiples
- 840, 1,680, 2,520, 3,360, 4,200, 5,040, 5,880, 6,720, 7,560, 8,400
- Square
- 840 × 840 = 705,600
- Square root
- ≈ 28.98
- Sum of the digits
- 8 + 4 + 0 = 12
- Rounded to the nearest 10
- 840
- Rounded to the nearest 100
- 800
- Number before
- 839
- Number after
- 841
- In binary
1101001000
Quick check
What number comes just after 840?
Show the answer
841
Is 840 even or odd?
Show the answer
Even
What is 840 + 10?
Show the answer
850
Practise with a game
Factors, Multiples & Primes
Multiples, factors, prime numbers, square numbers and prime factors.
Roman Numerals
Read and write Roman numerals from I to 3,999.Frequently asked questions
How do you write 840 in words?
840 is written "eight hundred and forty".
Is 840 a prime number?
No. 840 is a composite number, because it has more than two factors.
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 and 840.
How do you write 840 in Roman numerals?
840 in Roman numerals is DCCCXL.