The number 678
678 is a composite number with 8 divisors. Its prime factorisation is 2 × 3 × 113. Divisors (8): 1, 2, 3, 6, 113, 226, 339, 678.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
678 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
678 is composite. Its prime factorisation is
- 3
The divisors add up to 1368; without 678 itself that is 690, so 678 is abundant (690 is more than 678). Euler's totient φ(678) = 224 numbers up to 678 share no factor with it.
- 4
The digits of 678 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 51 steps to reach 1.
LaTeX source of the formulas on this page
\[ 678 = 2 \times 3 \times 113 \]
678 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 1368 |
| Euler totient φ(n) | 224 |
| Square | 459684 |
| Cube | 311665752 |
| Square root | 26.038433 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 51 |
| Scientific notation | 6.78 × |
678 in other forms
| Form | Value |
|---|---|
| In words | six hundred and seventy-eight |
| Roman numerals | DCLXXVIII |
| Binary (base 2) | 1010100110 |
| Octal (base 8) | 1246 |
| Hexadecimal (base 16) | 2A6 |
| Base 3 | 221010 |
| As time | 678 seconds = 11 min 18 s |
Is 678 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (678 ÷ 2 = 339) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (678 ÷ 3 = 226) | 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 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (678 ÷ 6 = 113) | 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 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | 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 678 a prime number?
No. 678 = 2 × 3 × 113, so it is divisible by 2.
What are the factors of 678?
1, 2, 3, 6, 113, 226, 339, 678.
What is 678 in binary?
1010100110 (hexadecimal 2A6, octal 1246).
What is the square root of 678?
About 26.0384.
What is 678 in Roman numerals?
DCLXXVIII.
Is 678 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 678?
It is a composite number with 8 divisors.