The number 78309
78309 is a composite number with 24 divisors. Its prime factorisation is × 7 × 11 × 113. Divisors (24): 1, 3, 7, 9, 11, 21, 33, 63, 77, 99, 113, 231, 339, 693, 791, 1017 … 78309.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 78309: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
78309 is composite. Its prime factorisation is
- 3
The divisors add up to 142272; without 78309 itself that is 63963, so 78309 is deficient (63963 is less than 78309). Euler's totient φ(78309) = 40320 numbers up to 78309 share no factor with it.
- 4
The digits of 78309 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 76 steps to reach 1.
LaTeX source of the formulas on this page
\[ 78309 = 3^{2} \times 7 \times 11 \times 113 \]78309 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 142272 |
| Euler totient φ(n) | 40320 |
| Square | 6132299481 |
| Cube | 480214240057629 |
| Square root | 279.837453 (= 3√8701) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 76 |
| Scientific notation | 7.8309 × |
78309 in other forms
| Form | Value |
|---|---|
| In words | seventy-eight thousand three hundred and nine |
| Binary (base 2) | 10011000111100101 |
| Octal (base 8) | 230745 |
| Hexadecimal (base 16) | 131E5 |
| Base 3 | 10222102100 |
| As time | 78309 seconds = 21 h 45 min 9 s |
Is 78309 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 (78309 ÷ 3 = 26103) | 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 | Yes (78309 ÷ 7 = 11187) | 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 | Yes (78309 ÷ 9 = 8701) | 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 | Yes (78309 ÷ 11 = 7119) | 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 78309 a prime number?
No. 78309 = × 7 × 11 × 113, so it is divisible by 3.
What are the factors of 78309?
1, 3, 7, 9, 11, 21, 33, 63, 77, 99, 113, 231, 339, 693, 791, 1017, 1243, 2373, 3729, 7119, 8701, 11187, 26103, 78309.
What is 78309 in binary?
10011000111100101 (hexadecimal 131E5, octal 230745).
What is the square root of 78309?
About 279.8375, exactly 3√8701.
Is 78309 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 78309?
78309 is a happy number: repeatedly adding the squares of its digits reaches 1.