21,421 in words
21,421
twenty-one thousand four hundred and twenty-one
21,421 is written twenty-one thousand four hundred and twenty-one.
Ways to write it
- As an ordinal
- twenty-one thousand four hundred and twenty-first
- Expanded form
- 20,000 + 1,000 + 400 + 20 + 1
Place value
| Place | Digit | Value |
|---|---|---|
| ten thousands | 2 | 20,000 |
| thousands | 1 | 1,000 |
| hundreds | 4 | 400 |
| tens | 2 | 20 |
| ones | 1 | 1 |
Number facts
- Even or odd
- Odd
- Prime or composite
- Composite
- Factors
- 1, 31, 691 and 21,421 (4 factors)
- First 10 multiples
- 21,421, 42,842, 64,263, 85,684, 107,105, 128,526, 149,947, 171,368, 192,789, 214,210
- Square
- 21,421 × 21,421 = 458,859,241
- Square root
- ≈ 146.36
- Sum of the digits
- 2 + 1 + 4 + 2 + 1 = 10
- Rounded to the nearest 10
- 21,420
- Rounded to the nearest 100
- 21,400
- Rounded to the nearest 1000
- 21,000
- Number before
- 21,420
- Number after
- 21,422
- In binary
101001110101101
Quick check
What number comes just after 21,421?
Show the answer
21,422
Is 21,421 even or odd?
Show the answer
Odd
What is 21,421 + 10?
Show the answer
21,431
Practise with a game
Factors, Multiples & Primes
Multiples, factors, prime numbers, square numbers and prime factors.
Number Patterns
Find the missing number in a sequence.Frequently asked questions
How do you write 21,421 in words?
21,421 is written "twenty-one thousand four hundred and twenty-one".
Is 21,421 a prime number?
No. 21,421 is a composite number, because it has more than two factors.
What are the factors of 21,421?
The factors of 21,421 are 1, 31, 691 and 21,421.