21,005 in words
21,005
twenty-one thousand and five
21,005 is written twenty-one thousand and five.
Ways to write it
- As an ordinal
- twenty-one thousand and fifth
- Expanded form
- 20,000 + 1,000 + 5
Place value
| Place | Digit | Value |
|---|---|---|
| ten thousands | 2 | 20,000 |
| thousands | 1 | 1,000 |
| hundreds | 0 | 0 |
| tens | 0 | 0 |
| ones | 5 | 5 |
Number facts
- Even or odd
- Odd
- Prime or composite
- Composite
- Factors
- 1, 5, 4,201 and 21,005 (4 factors)
- First 10 multiples
- 21,005, 42,010, 63,015, 84,020, 105,025, 126,030, 147,035, 168,040, 189,045, 210,050
- Square
- 21,005 × 21,005 = 441,210,025
- Square root
- ≈ 144.93
- Sum of the digits
- 2 + 1 + 0 + 0 + 5 = 8
- Rounded to the nearest 10
- 21,010
- Rounded to the nearest 100
- 21,000
- Rounded to the nearest 1000
- 21,000
- Number before
- 21,004
- Number after
- 21,006
- In binary
101001000001101
Quick check
What number comes just after 21,005?
Show the answer
21,006
Is 21,005 even or odd?
Show the answer
Odd
What is 21,005 + 10?
Show the answer
21,015
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 21,005 in words?
21,005 is written "twenty-one thousand and five".
Is 21,005 a prime number?
No. 21,005 is a composite number, because it has more than two factors.
What are the factors of 21,005?
The factors of 21,005 are 1, 5, 4,201 and 21,005.