21,997 in words
21,997
twenty-one thousand nine hundred and ninety-seven
21,997 is written twenty-one thousand nine hundred and ninety-seven.
Ways to write it
- As an ordinal
- twenty-one thousand nine hundred and ninety-seventh
- Expanded form
- 20,000 + 1,000 + 900 + 90 + 7
Place value
| Place | Digit | Value |
|---|---|---|
| ten thousands | 2 | 20,000 |
| thousands | 1 | 1,000 |
| hundreds | 9 | 900 |
| tens | 9 | 90 |
| ones | 7 | 7 |
Number facts
- Even or odd
- Odd
- Prime or composite
- Prime
- Factors
- 1 and 21,997 (2 factors)
- First 10 multiples
- 21,997, 43,994, 65,991, 87,988, 109,985, 131,982, 153,979, 175,976, 197,973, 219,970
- Square
- 21,997 × 21,997 = 483,868,009
- Square root
- ≈ 148.31
- Sum of the digits
- 2 + 1 + 9 + 9 + 7 = 28
- Rounded to the nearest 10
- 22,000
- Rounded to the nearest 100
- 22,000
- Rounded to the nearest 1000
- 22,000
- Number before
- 21,996
- Number after
- 21,998
- In binary
101010111101101
Quick check
What number comes just after 21,997?
Show the answer
21,998
Is 21,997 even or odd?
Show the answer
Odd
What is 21,997 + 10?
Show the answer
22,007
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 21,997 in words?
21,997 is written "twenty-one thousand nine hundred and ninety-seven".
Is 21,997 a prime number?
Yes. 21,997 is a prime number: its only factors are 1 and 21,997.
What are the factors of 21,997?
The factors of 21,997 are 1 and 21,997.