21,729 in words
21,729
twenty-one thousand seven hundred twenty-nine
21,729 is written twenty-one thousand seven hundred twenty-nine.
Ways to write it
- As an ordinal
- twenty-one thousand seven hundred twenty-ninth
- Expanded form
- 20,000 + 1,000 + 700 + 20 + 9
Place value
| Place | Digit | Value |
|---|---|---|
| ten thousands | 2 | 20,000 |
| thousands | 1 | 1,000 |
| hundreds | 7 | 700 |
| tens | 2 | 20 |
| ones | 9 | 9 |
Number facts
- Even or odd
- Odd
- Prime or composite
- Composite
- Factors
- 1, 3, 7,243 and 21,729 (4 factors)
- First 10 multiples
- 21,729, 43,458, 65,187, 86,916, 108,645, 130,374, 152,103, 173,832, 195,561, 217,290
- Square
- 21,729 × 21,729 = 472,149,441
- Square root
- ≈ 147.41
- Sum of the digits
- 2 + 1 + 7 + 2 + 9 = 21
- Rounded to the nearest 10
- 21,730
- Rounded to the nearest 100
- 21,700
- Rounded to the nearest 1000
- 22,000
- Number before
- 21,728
- Number after
- 21,730
- In binary
101010011100001
Quick check
What number comes just after 21,729?
Show the answer
21,730
Is 21,729 even or odd?
Show the answer
Odd
What is 21,729 + 10?
Show the answer
21,739
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 21,729 in words?
21,729 is written "twenty-one thousand seven hundred twenty-nine".
Is 21,729 a prime number?
No. 21,729 is a composite number, because it has more than two factors.
What are the factors of 21,729?
The factors of 21,729 are 1, 3, 7,243 and 21,729.