The number 868
868 is a palindrome: it reads 868 backwards too. Its prime factorisation is × 7 × 31. Divisors (12): 1, 2, 4, 7, 14, 28, 31, 62, 124, 217, 434, 868.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 868: a palindrome: it reads 868 backwards too.
- 2
868 is composite. Its prime factorisation is
- 3
The divisors add up to 1792; without 868 itself that is 924, so 868 is abundant (924 is more than 868). Euler's totient φ(868) = 360 numbers up to 868 share no factor with it.
- 4
The digits of 868 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 28 steps to reach 1.
LaTeX source of the formulas on this page
\[ 868 = 2^{2} \times 7 \times 31 \]868 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 1792 |
| Euler totient φ(n) | 360 |
| Square | 753424 |
| Cube | 653972032 |
| Square root | 29.461840 (= 2√217) |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 28 |
| Scientific notation | 8.68 × |
868 in other forms
| Form | Value |
|---|---|
| In words | eight hundred and sixty-eight |
| Roman numerals | DCCCLXVIII |
| Binary (base 2) | 1101100100 |
| Octal (base 8) | 1544 |
| Hexadecimal (base 16) | 364 |
| Base 3 | 1012011 |
| As time | 868 seconds = 14 min 28 s |
Is 868 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (868 ÷ 2 = 434) | 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 | Yes (868 ÷ 4 = 217) | 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 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (868 ÷ 7 = 124) | 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 4) | 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 | No (remainder 8) | 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 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 868 a prime number?
No. 868 = × 7 × 31, so it is divisible by 2.
What are the factors of 868?
1, 2, 4, 7, 14, 28, 31, 62, 124, 217, 434, 868.
What is 868 in binary?
1101100100 (hexadecimal 364, octal 1544).
What is the square root of 868?
About 29.4618, exactly 2√217.
What is 868 in Roman numerals?
DCCCLXVIII.
Is 868 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 868?
868 is a palindrome: it reads 868 backwards too.