21,731 in words
21,731
twenty-one thousand seven hundred thirty-one
21,731 is written twenty-one thousand seven hundred thirty-one.
Ways to write it
- As an ordinal
- twenty-one thousand seven hundred thirty-first
- Expanded form
- 20,000 + 1,000 + 700 + 30 + 1
Place value
| Place | Digit | Value |
|---|---|---|
| ten thousands | 2 | 20,000 |
| thousands | 1 | 1,000 |
| hundreds | 7 | 700 |
| tens | 3 | 30 |
| ones | 1 | 1 |
Number facts
- Even or odd
- Odd
- Prime or composite
- Composite
- Factors
- 1, 31, 701 and 21,731 (4 factors)
- First 10 multiples
- 21,731, 43,462, 65,193, 86,924, 108,655, 130,386, 152,117, 173,848, 195,579, 217,310
- Square
- 21,731 × 21,731 = 472,236,361
- Square root
- ≈ 147.41
- Sum of the digits
- 2 + 1 + 7 + 3 + 1 = 14
- Rounded to the nearest 10
- 21,730
- Rounded to the nearest 100
- 21,700
- Rounded to the nearest 1000
- 22,000
- Number before
- 21,730
- Number after
- 21,732
- In binary
101010011100011
Quick check
What number comes just after 21,731?
Show the answer
21,732
Is 21,731 even or odd?
Show the answer
Odd
What is 21,731 + 10?
Show the answer
21,741
Practise with a game
Factors, Multiples & Primes
Multiples, factors, prime numbers, square numbers and prime factors.
Number Patterns
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How do you write 21,731 in words?
21,731 is written "twenty-one thousand seven hundred thirty-one".
Is 21,731 a prime number?
No. 21,731 is a composite number, because it has more than two factors.
What are the factors of 21,731?
The factors of 21,731 are 1, 31, 701 and 21,731.