The number 21139
21139 is the 2375th prime number. Its only divisors are 1 and 21139.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21139: the 2375th prime number.
- 2
21139 is prime, so its only factors are 1 and 21139. It is the 2375th prime; the next prime is 21143 and the one before is 21121.
- 3
The divisors add up to 21140; without 21139 itself that is 1, so 21139 is deficient (1 is less than 21139). Euler's totient φ(21139) = 21138 numbers up to 21139 share no factor with it.
- 4
The digits of 21139 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
21139 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 21140 |
| Euler totient φ(n) | 21138 |
| Square | 446857321 |
| Cube | 9446116908619 |
| Square root | 145.392572 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1139 × |
21139 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and thirty-nine |
| Binary (base 2) | 101001010010011 |
| Octal (base 8) | 51223 |
| Hexadecimal (base 16) | 5293 |
| Base 3 | 1001222221 |
| As time | 21139 seconds = 5 h 52 min 19 s |
Is 21139 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 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 1) | 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 3) | 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 | No (remainder 9) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21139 a prime number?
Yes. 21139 is divisible only by 1 and itself.
What are the factors of 21139?
1, 21139.
What is 21139 in binary?
101001010010011 (hexadecimal 5293, octal 51223).
What is the square root of 21139?
About 145.3926.
Is 21139 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 21139?
21139 is the 2375th prime number.