The number 21310
21310 is a composite number with 8 divisors. Its prime factorisation is 2 × 5 × 2131. Divisors (8): 1, 2, 5, 10, 2131, 4262, 10655, 21310.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21310 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21310 is composite. Its prime factorisation is
- 3
The divisors add up to 38376; without 21310 itself that is 17066, so 21310 is deficient (17066 is less than 21310). Euler's totient φ(21310) = 8520 numbers up to 21310 share no factor with it.
- 4
The digits of 21310 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 149 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21310 = 2 \times 5 \times 2131 \]
21310 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 38376 |
| Euler totient φ(n) | 8520 |
| Square | 454116100 |
| Cube | 9677214091000 |
| Square root | 145.979451 |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 149 |
| Scientific notation | 2.131 × |
21310 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand three hundred and ten |
| Binary (base 2) | 101001100111110 |
| Octal (base 8) | 51476 |
| Hexadecimal (base 16) | 533E |
| Base 3 | 1002020021 |
| As time | 21310 seconds = 5 h 55 min 10 s |
Is 21310 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21310 ÷ 2 = 10655) | 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 (21310 ÷ 5 = 4262) | 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 2) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21310 ÷ 10 = 2131) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | 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 21310 a prime number?
No. 21310 = 2 × 5 × 2131, so it is divisible by 2.
What are the factors of 21310?
1, 2, 5, 10, 2131, 4262, 10655, 21310.
What is 21310 in binary?
101001100111110 (hexadecimal 533E, octal 51476).
What is the square root of 21310?
About 145.9795.
Is 21310 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 21310?
It is a composite number with 8 divisors.