The number 21613
21613 is a twin prime (21611 and 21613 are both prime) and the 2428th prime number. Its only divisors are 1 and 21613.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21613: a twin prime (21611 and 21613 are both prime); the 2428th prime number.
- 2
21613 is prime, so its only factors are 1 and 21613. It is the 2428th prime; the next prime is 21617 and the one before is 21611.
- 3
The divisors add up to 21614; without 21613 itself that is 1, so 21613 is deficient (1 is less than 21613). Euler's totient φ(21613) = 21612 numbers up to 21613 share no factor with it.
- 4
The digits of 21613 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 74 steps to reach 1.
21613 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 21614 |
| Euler totient φ(n) | 21612 |
| Square | 467121769 |
| Cube | 10095902793397 |
| Square root | 147.013605 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 74 |
| Scientific notation | 2.1613 × |
21613 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand six hundred and thirteen |
| Binary (base 2) | 101010001101101 |
| Octal (base 8) | 52155 |
| Hexadecimal (base 16) | 546D |
| Base 3 | 1002122111 |
| As time | 21613 seconds = 6 h 0 min 13 s |
Is 21613 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 1) | 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 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 5) | 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 | No (remainder 3) | 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21613 a prime number?
Yes. 21613 is divisible only by 1 and itself.
What are the factors of 21613?
1, 21613.
What is 21613 in binary?
101010001101101 (hexadecimal 546D, octal 52155).
What is the square root of 21613?
About 147.0136.
Is 21613 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 21613?
21613 is a twin prime (21611 and 21613 are both prime); the 2428th prime number.