400 in words
400
four hundred
400 is written four hundred.
Ways to write it
- As an ordinal
- four hundredth
- Roman numeral
- CD
- Expanded form
- 400
Place value
| Place | Digit | Value |
|---|---|---|
| hundreds | 4 | 400 |
| tens | 0 | 0 |
| ones | 0 | 0 |
Number facts
- Even or odd
- Even
- Prime or composite
- Composite
- Factors
- 1, 2, 4, 5, 8, 10, 16, 20, 25, 40, 50, 80, 100, 200 and 400 (15 factors)
- First 10 multiples
- 400, 800, 1,200, 1,600, 2,000, 2,400, 2,800, 3,200, 3,600, 4,000
- Square
- 400 × 400 = 160,000
- Square root
- 20
- Sum of the digits
- 4 + 0 + 0 = 4
- Rounded to the nearest 10
- 400
- Rounded to the nearest 100
- 400
- Number before
- 399
- Number after
- 401
- In binary
110010000
Quick check
What number comes just after 400?
Show the answer
401
Is 400 even or odd?
Show the answer
Even
What is 400 + 10?
Show the answer
410
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 400 in words?
400 is written "four hundred".
Is 400 a prime number?
No. 400 is a composite number, because it has more than two factors.
What are the factors of 400?
The factors of 400 are 1, 2, 4, 5, 8, 10, 16, 20, 25, 40, 50, 80, 100, 200 and 400.
How do you write 400 in Roman numerals?
400 in Roman numerals is CD.