The number 75855
75855 is a triangular number: 1 + 2 + … + 389 = 75855. Its prime factorisation is 3 × 5 × 13 × 389. Divisors (16): 1, 3, 5, 13, 15, 39, 65, 195, 389, 1167, 1945, 5057, 5835, 15171, 25285, 75855.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 75855: a triangular number: 1 + 2 + … + 389 = 75855; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
75855 is composite. Its prime factorisation is
- 3
The divisors add up to 131040; without 75855 itself that is 55185, so 75855 is deficient (55185 is less than 75855). Euler's totient φ(75855) = 37248 numbers up to 75855 share no factor with it.
- 4
The digits of 75855 add up to 30, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 156 steps to reach 1.
LaTeX source of the formulas on this page
\[ 75855 = 3 \times 5 \times 13 \times 389 \]
75855 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 131040 |
| Euler totient φ(n) | 37248 |
| Square | 5753981025 |
| Cube | 436468230651375 |
| Square root | 275.417864 |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 156 |
| Scientific notation | 7.5855 × |
75855 in other forms
| Form | Value |
|---|---|
| In words | seventy-five thousand eight hundred and fifty-five |
| Binary (base 2) | 10010100001001111 |
| Octal (base 8) | 224117 |
| Hexadecimal (base 16) | 1284F |
| Base 3 | 10212001110 |
| As time | 75855 seconds = 21 h 4 min 15 s |
Is 75855 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 (75855 ÷ 3 = 25285) | 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 | Yes (75855 ÷ 5 = 15171) | 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 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 75855 a prime number?
No. 75855 = 3 × 5 × 13 × 389, so it is divisible by 3.
What are the factors of 75855?
1, 3, 5, 13, 15, 39, 65, 195, 389, 1167, 1945, 5057, 5835, 15171, 25285, 75855.
What is 75855 in binary?
10010100001001111 (hexadecimal 1284F, octal 224117).
What is the square root of 75855?
About 275.4179.
Is 75855 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 75855?
75855 is a triangular number: 1 + 2 + … + 389 = 75855; a happy number: repeatedly adding the squares of its digits reaches 1.