The number 21059
21059 is a twin prime (21059 and 21061 are both prime) and the 2368th prime number. Its only divisors are 1 and 21059.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21059: a twin prime (21059 and 21061 are both prime); the 2368th prime number.
- 2
21059 is prime, so its only factors are 1 and 21059. It is the 2368th prime; the next prime is 21061 and the one before is 21031.
- 3
The divisors add up to 21060; without 21059 itself that is 1, so 21059 is deficient (1 is less than 21059). Euler's totient φ(21059) = 21058 numbers up to 21059 share no factor with it.
- 4
The digits of 21059 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 43 steps to reach 1.
21059 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 21060 |
| Euler totient φ(n) | 21058 |
| Square | 443481481 |
| Cube | 9339276508379 |
| Square root | 145.117194 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 43 |
| Scientific notation | 2.1059 × |
21059 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand and fifty-nine |
| Binary (base 2) | 101001001000011 |
| Octal (base 8) | 51103 |
| Hexadecimal (base 16) | 5243 |
| Base 3 | 1001212222 |
| As time | 21059 seconds = 5 h 50 min 59 s |
Is 21059 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | 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 3) | 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 3) | 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 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21059 a prime number?
Yes. 21059 is divisible only by 1 and itself.
What are the factors of 21059?
1, 21059.
What is 21059 in binary?
101001001000011 (hexadecimal 5243, octal 51103).
What is the square root of 21059?
About 145.1172.
Is 21059 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21059?
21059 is a twin prime (21059 and 21061 are both prime); the 2368th prime number.