The number 77790
77790 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 5 × 2593. Divisors (16): 1, 2, 3, 5, 6, 10, 15, 30, 2593, 5186, 7779, 12965, 15558, 25930, 38895, 77790.
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How to work it out
- 1
What is special about 77790: a Harshad number: divisible by its digit sum 30.
- 2
77790 is composite. Its prime factorisation is
- 3
The divisors add up to 186768; without 77790 itself that is 108978, so 77790 is abundant (108978 is more than 77790). Euler's totient φ(77790) = 20736 numbers up to 77790 share no factor with it.
- 4
The digits of 77790 add up to 30, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 169 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77790 = 2 \times 3 \times 5 \times 2593 \]
77790 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 186768 |
| Euler totient φ(n) | 20736 |
| Square | 6051284100 |
| Cube | 470729390139000 |
| Square root | 278.908587 |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 169 |
| Scientific notation | 7.779 × |
77790 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand seven hundred and ninety |
| Binary (base 2) | 10010111111011110 |
| Octal (base 8) | 227736 |
| Hexadecimal (base 16) | 12FDE |
| Base 3 | 10221201010 |
| As time | 77790 seconds = 21 h 36 min 30 s |
Is 77790 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (77790 ÷ 2 = 38895) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (77790 ÷ 3 = 25930) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (77790 ÷ 5 = 15558) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (77790 ÷ 6 = 12965) | 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 6) | 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 | Yes (77790 ÷ 10 = 7779) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77790 a prime number?
No. 77790 = 2 × 3 × 5 × 2593, so it is divisible by 2.
What are the factors of 77790?
1, 2, 3, 5, 6, 10, 15, 30, 2593, 5186, 7779, 12965, 15558, 25930, 38895, 77790.
What is 77790 in binary?
10010111111011110 (hexadecimal 12FDE, octal 227736).
What is the square root of 77790?
About 278.9086.
Is 77790 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 77790?
77790 is a Harshad number: divisible by its digit sum 30.