21,724 in words
21,724
twenty-one thousand seven hundred twenty-four
21,724 is written twenty-one thousand seven hundred twenty-four.
Ways to write it
- As an ordinal
- twenty-one thousand seven hundred twenty-fourth
- Expanded form
- 20,000 + 1,000 + 700 + 20 + 4
Place value
| Place | Digit | Value |
|---|---|---|
| ten thousands | 2 | 20,000 |
| thousands | 1 | 1,000 |
| hundreds | 7 | 700 |
| tens | 2 | 20 |
| ones | 4 | 4 |
Number facts
- Even or odd
- Even
- Prime or composite
- Composite
- Factors
- 1, 2, 4, 5,431, 10,862 and 21,724 (6 factors)
- First 10 multiples
- 21,724, 43,448, 65,172, 86,896, 108,620, 130,344, 152,068, 173,792, 195,516, 217,240
- Square
- 21,724 × 21,724 = 471,932,176
- Square root
- ≈ 147.39
- Sum of the digits
- 2 + 1 + 7 + 2 + 4 = 16
- Rounded to the nearest 10
- 21,720
- Rounded to the nearest 100
- 21,700
- Rounded to the nearest 1000
- 22,000
- Number before
- 21,723
- Number after
- 21,725
- In binary
101010011011100
Quick check
What number comes just after 21,724?
Show the answer
21,725
Is 21,724 even or odd?
Show the answer
Even
What is 21,724 + 10?
Show the answer
21,734
Practice 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 21,724 in words?
21,724 is written "twenty-one thousand seven hundred twenty-four".
Is 21,724 a prime number?
No. 21,724 is a composite number, because it has more than two factors.
What are the factors of 21,724?
The factors of 21,724 are 1, 2, 4, 5,431, 10,862 and 21,724.