21,123 in words
21,123
twenty-one thousand one hundred twenty-three
21,123 is written twenty-one thousand one hundred twenty-three.
Ways to write it
- As an ordinal
- twenty-one thousand one hundred twenty-third
- Expanded form
- 20,000 + 1,000 + 100 + 20 + 3
Place value
| Place | Digit | Value |
|---|---|---|
| ten thousands | 2 | 20,000 |
| thousands | 1 | 1,000 |
| hundreds | 1 | 100 |
| tens | 2 | 20 |
| ones | 3 | 3 |
Number facts
- Even or odd
- Odd
- Prime or composite
- Composite
- Factors
- 1, 3, 9, 2,347, 7,041 and 21,123 (6 factors)
- First 10 multiples
- 21,123, 42,246, 63,369, 84,492, 105,615, 126,738, 147,861, 168,984, 190,107, 211,230
- Square
- 21,123 × 21,123 = 446,181,129
- Square root
- ≈ 145.34
- Sum of the digits
- 2 + 1 + 1 + 2 + 3 = 9
- Rounded to the nearest 10
- 21,120
- Rounded to the nearest 100
- 21,100
- Rounded to the nearest 1000
- 21,000
- Number before
- 21,122
- Number after
- 21,124
- In binary
101001010000011
Quick check
What number comes just after 21,123?
Show the answer
21,124
Is 21,123 even or odd?
Show the answer
Odd
What is 21,123 + 10?
Show the answer
21,133
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 21,123 in words?
21,123 is written "twenty-one thousand one hundred twenty-three".
Is 21,123 a prime number?
No. 21,123 is a composite number, because it has more than two factors.
What are the factors of 21,123?
The factors of 21,123 are 1, 3, 9, 2,347, 7,041 and 21,123.