The number 77979
77979 is a composite number with 16 divisors. Its prime factorisation is 3 × 11 × 17 × 139. Divisors (16): 1, 3, 11, 17, 33, 51, 139, 187, 417, 561, 1529, 2363, 4587, 7089, 25993, 77979.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
77979 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
77979 is composite. Its prime factorisation is
- 3
The divisors add up to 120960; without 77979 itself that is 42981, so 77979 is deficient (42981 is less than 77979). Euler's totient φ(77979) = 44160 numbers up to 77979 share no factor with it.
- 4
The digits of 77979 add up to 39, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 200 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77979 = 3 \times 11 \times 17 \times 139 \]
77979 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 120960 |
| Euler totient φ(n) | 44160 |
| Square | 6080724441 |
| Cube | 474168811184739 |
| Square root | 279.247202 |
| Digit sum / digital root | 39 / 3 |
| Collatz steps to 1 | 200 |
| Scientific notation | 7.7979 × |
77979 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand nine hundred and seventy-nine |
| Binary (base 2) | 10011000010011011 |
| Octal (base 8) | 230233 |
| Hexadecimal (base 16) | 1309B |
| Base 3 | 10221222010 |
| As time | 77979 seconds = 21 h 39 min 39 s |
Is 77979 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 (77979 ÷ 3 = 25993) | 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 4) | 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 6) | 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 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (77979 ÷ 11 = 7089) | 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 77979 a prime number?
No. 77979 = 3 × 11 × 17 × 139, so it is divisible by 3.
What are the factors of 77979?
1, 3, 11, 17, 33, 51, 139, 187, 417, 561, 1529, 2363, 4587, 7089, 25993, 77979.
What is 77979 in binary?
10011000010011011 (hexadecimal 1309B, octal 230233).
What is the square root of 77979?
About 279.2472.
Is 77979 divisible by 3?
Yes. Its digits add up to 39, a multiple of 3.
What is special about the number 77979?
It is a composite number with 16 divisors.