The number 21617
21617 is the 2429th prime number. Its only divisors are 1 and 21617.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21617: the 2429th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
21617 is prime, so its only factors are 1 and 21617. It is the 2429th prime; the next prime is 21647 and the one before is 21613.
- 3
The divisors add up to 21618; without 21617 itself that is 1, so 21617 is deficient (1 is less than 21617). Euler's totient φ(21617) = 21616 numbers up to 21617 share no factor with it.
- 4
The digits of 21617 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 118 steps to reach 1.
21617 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 21618 |
| Euler totient φ(n) | 21616 |
| Square | 467294689 |
| Cube | 10101509292113 |
| Square root | 147.027208 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 118 |
| Scientific notation | 2.1617 × |
21617 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand six hundred and seventeen |
| Binary (base 2) | 101010001110001 |
| Octal (base 8) | 52161 |
| Hexadecimal (base 16) | 5471 |
| Base 3 | 1002122122 |
| As time | 21617 seconds = 6 h 0 min 17 s |
Is 21617 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 1) | 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 | No (remainder 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21617 a prime number?
Yes. 21617 is divisible only by 1 and itself.
What are the factors of 21617?
1, 21617.
What is 21617 in binary?
101010001110001 (hexadecimal 5471, octal 52161).
What is the square root of 21617?
About 147.0272.
Is 21617 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21617?
21617 is the 2429th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.