The number 77985
77985 is a composite number with 12 divisors. Its prime factorisation is × 5 × 1733. Divisors (12): 1, 3, 5, 9, 15, 45, 1733, 5199, 8665, 15597, 25995, 77985.
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How to work it out
- 1
77985 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
77985 is composite. Its prime factorisation is
- 3
The divisors add up to 135252; without 77985 itself that is 57267, so 77985 is deficient (57267 is less than 77985). Euler's totient φ(77985) = 41568 numbers up to 77985 share no factor with it.
- 4
The digits of 77985 add up to 36, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 107 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77985 = 3^{2} \times 5 \times 1733 \]77985 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 135252 |
| Euler totient φ(n) | 41568 |
| Square | 6081660225 |
| Cube | 474278272646625 |
| Square root | 279.257945 (= 3√8665) |
| Digit sum / digital root | 36 / 9 |
| Collatz steps to 1 | 107 |
| Scientific notation | 7.7985 × |
77985 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand nine hundred and eighty-five |
| Binary (base 2) | 10011000010100001 |
| Octal (base 8) | 230241 |
| Hexadecimal (base 16) | 130A1 |
| Base 3 | 10221222100 |
| As time | 77985 seconds = 21 h 39 min 45 s |
Is 77985 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 (77985 ÷ 3 = 25995) | 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 | Yes (77985 ÷ 5 = 15597) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (77985 ÷ 9 = 8665) | 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 6) | 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 77985 a prime number?
No. 77985 = × 5 × 1733, so it is divisible by 3.
What are the factors of 77985?
1, 3, 5, 9, 15, 45, 1733, 5199, 8665, 15597, 25995, 77985.
What is 77985 in binary?
10011000010100001 (hexadecimal 130A1, octal 230241).
What is the square root of 77985?
About 279.2579, exactly 3√8665.
Is 77985 divisible by 3?
Yes. Its digits add up to 36, a multiple of 3.
What is special about the number 77985?
It is a composite number with 12 divisors.