The number 77720
77720 is a composite number with 32 divisors. Its prime factorisation is × 5 × 29 × 67. Divisors (32): 1, 2, 4, 5, 8, 10, 20, 29, 40, 58, 67, 116, 134, 145, 232, 268 … 77720.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
77720 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
77720 is composite. Its prime factorisation is
- 3
The divisors add up to 183600; without 77720 itself that is 105880, so 77720 is abundant (105880 is more than 77720). Euler's totient φ(77720) = 29568 numbers up to 77720 share no factor with it.
- 4
The digits of 77720 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 169 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77720 = 2^{3} \times 5 \times 29 \times 67 \]77720 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 183600 |
| Euler totient φ(n) | 29568 |
| Square | 6040398400 |
| Cube | 469459763648000 |
| Square root | 278.783070 (= 2√19430) |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 169 |
| Scientific notation | 7.772 × |
77720 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand seven hundred and twenty |
| Binary (base 2) | 10010111110011000 |
| Octal (base 8) | 227630 |
| Hexadecimal (base 16) | 12F98 |
| Base 3 | 10221121112 |
| As time | 77720 seconds = 21 h 35 min 20 s |
Is 77720 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (77720 ÷ 2 = 38860) | 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 | Yes (77720 ÷ 4 = 19430) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (77720 ÷ 5 = 15544) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 | Yes (77720 ÷ 8 = 9715) | 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 | Yes (77720 ÷ 10 = 7772) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77720 a prime number?
No. 77720 = × 5 × 29 × 67, so it is divisible by 2.
What are the factors of 77720?
1, 2, 4, 5, 8, 10, 20, 29, 40, 58, 67, 116, 134, 145, 232, 268, 290, 335, 536, 580, 670, 1160, 1340, 1943, 2680, 3886, 7772, 9715, 15544, 19430, 38860, 77720.
What is 77720 in binary?
10010111110011000 (hexadecimal 12F98, octal 227630).
What is the square root of 77720?
About 278.7831, exactly 2√19430.
Is 77720 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 77720?
It is a composite number with 32 divisors.