The number 77121
77121 is a composite number with 24 divisors. Its prime factorisation is × 11 × 19 × 41. Divisors (24): 1, 3, 9, 11, 19, 33, 41, 57, 99, 123, 171, 209, 369, 451, 627, 779 … 77121.
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How to work it out
- 1
77121 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
77121 is composite. Its prime factorisation is
- 3
The divisors add up to 131040; without 77121 itself that is 53919, so 77121 is deficient (53919 is less than 77121). Euler's totient φ(77121) = 43200 numbers up to 77121 share no factor with it.
- 4
The digits of 77121 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 125 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77121 = 3^{2} \times 11 \times 19 \times 41 \]77121 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 131040 |
| Euler totient φ(n) | 43200 |
| Square | 5947648641 |
| Cube | 458688610842561 |
| Square root | 277.706680 (= 3√8569) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 125 |
| Scientific notation | 7.7121 × |
77121 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand one hundred and twenty-one |
| Binary (base 2) | 10010110101000001 |
| Octal (base 8) | 226501 |
| Hexadecimal (base 16) | 12D41 |
| Base 3 | 10220210100 |
| As time | 77121 seconds = 21 h 25 min 21 s |
Is 77121 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 (77121 ÷ 3 = 25707) | 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 1) | 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 2) | 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 (77121 ÷ 9 = 8569) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (77121 ÷ 11 = 7011) | 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 77121 a prime number?
No. 77121 = × 11 × 19 × 41, so it is divisible by 3.
What are the factors of 77121?
1, 3, 9, 11, 19, 33, 41, 57, 99, 123, 171, 209, 369, 451, 627, 779, 1353, 1881, 2337, 4059, 7011, 8569, 25707, 77121.
What is 77121 in binary?
10010110101000001 (hexadecimal 12D41, octal 226501).
What is the square root of 77121?
About 277.7067, exactly 3√8569.
Is 77121 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 77121?
It is a composite number with 24 divisors.