The number 789
789 is a composite number with 4 divisors. Its prime factorisation is 3 × 263. Divisors (4): 1, 3, 263, 789.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 789: a semiprime: 3 × 263, the product of two primes.
- 2
789 is composite. Its prime factorisation is
- 3
The divisors add up to 1056; without 789 itself that is 267, so 789 is deficient (267 is less than 789). Euler's totient φ(789) = 524 numbers up to 789 share no factor with it.
- 4
The digits of 789 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 28 steps to reach 1.
LaTeX source of the formulas on this page
\[ 789 = 3 \times 263 \]
789 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1056 |
| Euler totient φ(n) | 524 |
| Square | 622521 |
| Cube | 491169069 |
| Square root | 28.089144 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 28 |
| Scientific notation | 7.89 × |
789 in other forms
| Form | Value |
|---|---|
| In words | seven hundred and eighty-nine |
| Roman numerals | DCCLXXXIX |
| Binary (base 2) | 1100010101 |
| Octal (base 8) | 1425 |
| Hexadecimal (base 16) | 315 |
| Base 3 | 1002020 |
| As time | 789 seconds = 13 min 9 s |
Is 789 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 | Yes (789 ÷ 3 = 263) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 6) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 789 a prime number?
No. 789 = 3 × 263, so it is divisible by 3.
What are the factors of 789?
1, 3, 263, 789.
What is 789 in binary?
1100010101 (hexadecimal 315, octal 1425).
What is the square root of 789?
About 28.0891.
What is 789 in Roman numerals?
DCCLXXXIX.
Is 789 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 789?
789 is a semiprime: 3 × 263, the product of two primes.