The number 77931
77931 is a composite number with 12 divisors. Its prime factorisation is × 7 × 1237. Divisors (12): 1, 3, 7, 9, 21, 63, 1237, 3711, 8659, 11133, 25977, 77931.
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How to work it out
- 1
77931 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
77931 is composite. Its prime factorisation is
- 3
The divisors add up to 128752; without 77931 itself that is 50821, so 77931 is deficient (50821 is less than 77931). Euler's totient φ(77931) = 44496 numbers up to 77931 share no factor with it.
- 4
The digits of 77931 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 169 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77931 = 3^{2} \times 7 \times 1237 \]77931 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 128752 |
| Euler totient φ(n) | 44496 |
| Square | 6073240761 |
| Cube | 473293725745491 |
| Square root | 279.161244 (= 3√8659) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 169 |
| Scientific notation | 7.7931 × |
77931 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand nine hundred and thirty-one |
| Binary (base 2) | 10011000001101011 |
| Octal (base 8) | 230153 |
| Hexadecimal (base 16) | 1306B |
| Base 3 | 10221220100 |
| As time | 77931 seconds = 21 h 38 min 51 s |
Is 77931 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 (77931 ÷ 3 = 25977) | 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 | 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 | Yes (77931 ÷ 7 = 11133) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (77931 ÷ 9 = 8659) | 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 | No (remainder 7) | 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 77931 a prime number?
No. 77931 = × 7 × 1237, so it is divisible by 3.
What are the factors of 77931?
1, 3, 7, 9, 21, 63, 1237, 3711, 8659, 11133, 25977, 77931.
What is 77931 in binary?
10011000001101011 (hexadecimal 1306B, octal 230153).
What is the square root of 77931?
About 279.1612, exactly 3√8659.
Is 77931 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 77931?
It is a composite number with 12 divisors.