The number 77729
77729 is a composite number with 4 divisors. Its prime factorisation is 19 × 4091. Divisors (4): 1, 19, 4091, 77729.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 77729: a semiprime: 19 × 4091, the product of two primes.
- 2
77729 is composite. Its prime factorisation is
- 3
The divisors add up to 81840; without 77729 itself that is 4111, so 77729 is deficient (4111 is less than 77729). Euler's totient φ(77729) = 73620 numbers up to 77729 share no factor with it.
- 4
The digits of 77729 add up to 32, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 63 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77729 = 19 \times 4091 \]
77729 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 81840 |
| Euler totient φ(n) | 73620 |
| Square | 6041797441 |
| Cube | 469622873291489 |
| Square root | 278.799211 |
| Digit sum / digital root | 32 / 5 |
| Collatz steps to 1 | 63 |
| Scientific notation | 7.7729 × |
77729 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand seven hundred and twenty-nine |
| Binary (base 2) | 10010111110100001 |
| Octal (base 8) | 227641 |
| Hexadecimal (base 16) | 12FA1 |
| Base 3 | 10221121212 |
| As time | 77729 seconds = 21 h 35 min 29 s |
Is 77729 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 4) | 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 5) | 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 | No (remainder 3) | 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 77729 a prime number?
No. 77729 = 19 × 4091, so it is divisible by 19.
What are the factors of 77729?
1, 19, 4091, 77729.
What is 77729 in binary?
10010111110100001 (hexadecimal 12FA1, octal 227641).
What is the square root of 77729?
About 278.7992.
Is 77729 divisible by 3?
No. Its digits add up to 32, which is not a multiple of 3.
What is special about the number 77729?
77729 is a semiprime: 19 × 4091, the product of two primes.