The number 21370
21370 is a composite number with 8 divisors. Its prime factorisation is 2 × 5 × 2137. Divisors (8): 1, 2, 5, 10, 2137, 4274, 10685, 21370.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21370 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21370 is composite. Its prime factorisation is
- 3
The divisors add up to 38484; without 21370 itself that is 17114, so 21370 is deficient (17114 is less than 21370). Euler's totient φ(21370) = 8544 numbers up to 21370 share no factor with it.
- 4
The digits of 21370 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 48 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21370 = 2 \times 5 \times 2137 \]
21370 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 38484 |
| Euler totient φ(n) | 8544 |
| Square | 456676900 |
| Cube | 9759185353000 |
| Square root | 146.184815 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 48 |
| Scientific notation | 2.137 × |
21370 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand three hundred and seventy |
| Binary (base 2) | 101001101111010 |
| Octal (base 8) | 51572 |
| Hexadecimal (base 16) | 537A |
| Base 3 | 1002022111 |
| As time | 21370 seconds = 5 h 56 min 10 s |
Is 21370 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21370 ÷ 2 = 10685) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (21370 ÷ 5 = 4274) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21370 ÷ 10 = 2137) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21370 a prime number?
No. 21370 = 2 × 5 × 2137, so it is divisible by 2.
What are the factors of 21370?
1, 2, 5, 10, 2137, 4274, 10685, 21370.
What is 21370 in binary?
101001101111010 (hexadecimal 537A, octal 51572).
What is the square root of 21370?
About 146.1848.
Is 21370 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 21370?
It is a composite number with 8 divisors.