21,531 in words
21,531
twenty-one thousand five hundred thirty-one
21,531 is written twenty-one thousand five hundred thirty-one.
Ways to write it
- As an ordinal
- twenty-one thousand five hundred thirty-first
- Expanded form
- 20,000 + 1,000 + 500 + 30 + 1
Place value
| Place | Digit | Value |
|---|---|---|
| ten thousands | 2 | 20,000 |
| thousands | 1 | 1,000 |
| hundreds | 5 | 500 |
| tens | 3 | 30 |
| ones | 1 | 1 |
Number facts
- Even or odd
- Odd
- Prime or composite
- Composite
- Factors
- 1, 3, 7,177 and 21,531 (4 factors)
- First 10 multiples
- 21,531, 43,062, 64,593, 86,124, 107,655, 129,186, 150,717, 172,248, 193,779, 215,310
- Square
- 21,531 × 21,531 = 463,583,961
- Square root
- ≈ 146.73
- Sum of the digits
- 2 + 1 + 5 + 3 + 1 = 12
- Rounded to the nearest 10
- 21,530
- Rounded to the nearest 100
- 21,500
- Rounded to the nearest 1000
- 22,000
- Number before
- 21,530
- Number after
- 21,532
- In binary
101010000011011
Quick check
What number comes just after 21,531?
Show the answer
21,532
Is 21,531 even or odd?
Show the answer
Odd
What is 21,531 + 10?
Show the answer
21,541
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 21,531 in words?
21,531 is written "twenty-one thousand five hundred thirty-one".
Is 21,531 a prime number?
No. 21,531 is a composite number, because it has more than two factors.
What are the factors of 21,531?
The factors of 21,531 are 1, 3, 7,177 and 21,531.