The number 21140
21140 is a composite number with 24 divisors. Its prime factorisation is × 5 × 7 × 151. Divisors (24): 1, 2, 4, 5, 7, 10, 14, 20, 28, 35, 70, 140, 151, 302, 604, 755 … 21140.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21140 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21140 is composite. Its prime factorisation is
- 3
The divisors add up to 51072; without 21140 itself that is 29932, so 21140 is abundant (29932 is more than 21140). Euler's totient φ(21140) = 7200 numbers up to 21140 share no factor with it.
- 4
The digits of 21140 add up to 8, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 105 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21140 = 2^{2} \times 5 \times 7 \times 151 \]21140 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 51072 |
| Euler totient φ(n) | 7200 |
| Square | 446899600 |
| Cube | 9447457544000 |
| Square root | 145.396011 (= 2√5285) |
| Digit sum / digital root | 8 / 8 |
| Collatz steps to 1 | 105 |
| Scientific notation | 2.114 × |
21140 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and forty |
| Binary (base 2) | 101001010010100 |
| Octal (base 8) | 51224 |
| Hexadecimal (base 16) | 5294 |
| Base 3 | 1001222222 |
| As time | 21140 seconds = 5 h 52 min 20 s |
Is 21140 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21140 ÷ 2 = 10570) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21140 ÷ 4 = 5285) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (21140 ÷ 5 = 4228) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (21140 ÷ 7 = 3020) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21140 ÷ 10 = 2114) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21140 a prime number?
No. 21140 = × 5 × 7 × 151, so it is divisible by 2.
What are the factors of 21140?
1, 2, 4, 5, 7, 10, 14, 20, 28, 35, 70, 140, 151, 302, 604, 755, 1057, 1510, 2114, 3020, 4228, 5285, 10570, 21140.
What is 21140 in binary?
101001010010100 (hexadecimal 5294, octal 51224).
What is the square root of 21140?
About 145.3960, exactly 2√5285.
Is 21140 divisible by 3?
No. Its digits add up to 8, which is not a multiple of 3.
What is special about the number 21140?
It is a composite number with 24 divisors.