The number 77890
77890 is a composite number with 8 divisors. Its prime factorisation is 2 × 5 × 7789. Divisors (8): 1, 2, 5, 10, 7789, 15578, 38945, 77890.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
77890 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
77890 is composite. Its prime factorisation is
- 3
The divisors add up to 140220; without 77890 itself that is 62330, so 77890 is deficient (62330 is less than 77890). Euler's totient φ(77890) = 31152 numbers up to 77890 share no factor with it.
- 4
The digits of 77890 add up to 31, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 50 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77890 = 2 \times 5 \times 7789 \]
77890 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 140220 |
| Euler totient φ(n) | 31152 |
| Square | 6066852100 |
| Cube | 472547110069000 |
| Square root | 279.087800 |
| Digit sum / digital root | 31 / 4 |
| Collatz steps to 1 | 50 |
| Scientific notation | 7.789 × |
77890 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand eight hundred and ninety |
| Binary (base 2) | 10011000001000010 |
| Octal (base 8) | 230102 |
| Hexadecimal (base 16) | 13042 |
| Base 3 | 10221211211 |
| As time | 77890 seconds = 21 h 38 min 10 s |
Is 77890 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (77890 ÷ 2 = 38945) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | 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 (77890 ÷ 5 = 15578) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (77890 ÷ 10 = 7789) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77890 a prime number?
No. 77890 = 2 × 5 × 7789, so it is divisible by 2.
What are the factors of 77890?
1, 2, 5, 10, 7789, 15578, 38945, 77890.
What is 77890 in binary?
10011000001000010 (hexadecimal 13042, octal 230102).
What is the square root of 77890?
About 279.0878.
Is 77890 divisible by 3?
No. Its digits add up to 31, which is not a multiple of 3.
What is special about the number 77890?
It is a composite number with 8 divisors.