The number 77561
77561 is a composite number with 6 divisors. Its prime factorisation is Ć 641. Divisors (6): 1, 11, 121, 641, 7051, 77561.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
77561 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
77561 is composite. Its prime factorisation is
- 3
The divisors add up to 85386; without 77561 itself that is 7825, so 77561 is deficient (7825 is less than 77561). Euler's totient Ļ(77561) = 70400 numbers up to 77561 share no factor with it.
- 4
The digits of 77561 add up to 26, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 76 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77561 = 11^{2} \times 641 \]77561 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 85386 |
| Euler totient Ļ(n) | 70400 |
| Square | 6015708721 |
| Cube | 466584384109481 |
| Square root | 278.497756 (= 11ā641) |
| Digit sum / digital root | 26 / 8 |
| Collatz steps to 1 | 76 |
| Scientific notation | 7.7561 Ć |
77561 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand five hundred and sixty-one |
| Binary (base 2) | 10010111011111001 |
| Octal (base 8) | 227371 |
| Hexadecimal (base 16) | 12EF9 |
| Base 3 | 10221101122 |
| As time | 77561 seconds = 21 h 32 min 41 s |
Is 77561 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 | No (remainder 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 | No (remainder 8) | 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 (77561 Ć· 11 = 7051) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77561 a prime number?
No. 77561 = Ć 641, so it is divisible by 11.
What are the factors of 77561?
1, 11, 121, 641, 7051, 77561.
What is 77561 in binary?
10010111011111001 (hexadecimal 12EF9, octal 227371).
What is the square root of 77561?
About 278.4978, exactly 11ā641.
Is 77561 divisible by 3?
No. Its digits add up to 26, which is not a multiple of 3.
What is special about the number 77561?
It is a composite number with 6 divisors.