The number 2789
2789 is a twin prime (2789 and 2791 are both prime) and the 405th prime number. Its only divisors are 1 and 2789.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 2789: a twin prime (2789 and 2791 are both prime); the 405th prime number.
- 2
2789 is prime, so its only factors are 1 and 2789. It is the 405th prime; the next prime is 2791 and the one before is 2777.
- 3
The divisors add up to 2790; without 2789 itself that is 1, so 2789 is deficient (1 is less than 2789). Euler's totient φ(2789) = 2788 numbers up to 2789 share no factor with it.
- 4
The digits of 2789 add up to 26, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 128 steps to reach 1.
2789 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 2790 |
| Euler totient φ(n) | 2788 |
| Square | 7778521 |
| Cube | 21694295069 |
| Square root | 52.810984 |
| Digit sum / digital root | 26 / 8 |
| Collatz steps to 1 | 128 |
| Scientific notation | 2.789 × |
2789 in other forms
| Form | Value |
|---|---|
| In words | two thousand seven hundred and eighty-nine |
| Roman numerals | MMDCCLXXXIX |
| Binary (base 2) | 101011100101 |
| Octal (base 8) | 5345 |
| Hexadecimal (base 16) | AE5 |
| Base 3 | 10211022 |
| As time | 2789 seconds = 46 min 29 s |
Is 2789 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 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 5) | 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 6) | 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 2789 a prime number?
Yes. 2789 is divisible only by 1 and itself.
What are the factors of 2789?
1, 2789.
What is 2789 in binary?
101011100101 (hexadecimal AE5, octal 5345).
What is the square root of 2789?
About 52.8110.
What is 2789 in Roman numerals?
MMDCCLXXXIX.
Is 2789 divisible by 3?
No. Its digits add up to 26, which is not a multiple of 3.
What is special about the number 2789?
2789 is a twin prime (2789 and 2791 are both prime); the 405th prime number.