3,821 in words
3,821
three thousand eight hundred twenty-one
3,821 is written three thousand eight hundred twenty-one.
Ways to write it
- As an ordinal
- three thousand eight hundred twenty-first
- Roman numeral
- MMMDCCCXXI
- Expanded form
- 3,000 + 800 + 20 + 1
Place value
| Place | Digit | Value |
|---|---|---|
| thousands | 3 | 3,000 |
| hundreds | 8 | 800 |
| tens | 2 | 20 |
| ones | 1 | 1 |
Number facts
- Even or odd
- Odd
- Prime or composite
- Prime
- Factors
- 1 and 3,821 (2 factors)
- First 10 multiples
- 3,821, 7,642, 11,463, 15,284, 19,105, 22,926, 26,747, 30,568, 34,389, 38,210
- Square
- 3,821 × 3,821 = 14,600,041
- Square root
- ≈ 61.81
- Sum of the digits
- 3 + 8 + 2 + 1 = 14
- Rounded to the nearest 10
- 3,820
- Rounded to the nearest 100
- 3,800
- Rounded to the nearest 1000
- 4,000
- Number before
- 3,820
- Number after
- 3,822
- In binary
111011101101
Quick check
What number comes just after 3,821?
Show the answer
3,822
Is 3,821 even or odd?
Show the answer
Odd
What is 3,821 + 10?
Show the answer
3,831
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 3,821 in words?
3,821 is written "three thousand eight hundred twenty-one".
Is 3,821 a prime number?
Yes. 3,821 is a prime number: its only factors are 1 and 3,821.
What are the factors of 3,821?
The factors of 3,821 are 1 and 3,821.
How do you write 3,821 in Roman numerals?
3,821 in Roman numerals is MMMDCCCXXI.