The number 858
858 is a palindrome: it reads 858 backwards too. Its prime factorisation is 2 × 3 × 11 × 13. Divisors (16): 1, 2, 3, 6, 11, 13, 22, 26, 33, 39, 66, 78, 143, 286, 429, 858.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 858: a palindrome: it reads 858 backwards too.
- 2
858 is composite. Its prime factorisation is
- 3
The divisors add up to 2016; without 858 itself that is 1158, so 858 is abundant (1158 is more than 858). Euler's totient φ(858) = 240 numbers up to 858 share no factor with it.
- 4
The digits of 858 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 103 steps to reach 1.
LaTeX source of the formulas on this page
\[ 858 = 2 \times 3 \times 11 \times 13 \]
858 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 2016 |
| Euler totient φ(n) | 240 |
| Square | 736164 |
| Cube | 631628712 |
| Square root | 29.291637 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 103 |
| Scientific notation | 8.58 × |
858 in other forms
| Form | Value |
|---|---|
| In words | eight hundred and fifty-eight |
| Roman numerals | DCCCLVIII |
| Binary (base 2) | 1101011010 |
| Octal (base 8) | 1532 |
| Hexadecimal (base 16) | 35A |
| Base 3 | 1011210 |
| As time | 858 seconds = 14 min 18 s |
Is 858 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (858 ÷ 2 = 429) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (858 ÷ 3 = 286) | 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 (858 ÷ 6 = 143) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 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 | Yes (858 ÷ 11 = 78) | 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 858 a prime number?
No. 858 = 2 × 3 × 11 × 13, so it is divisible by 2.
What are the factors of 858?
1, 2, 3, 6, 11, 13, 22, 26, 33, 39, 66, 78, 143, 286, 429, 858.
What is 858 in binary?
1101011010 (hexadecimal 35A, octal 1532).
What is the square root of 858?
About 29.2916.
What is 858 in Roman numerals?
DCCCLVIII.
Is 858 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 858?
858 is a palindrome: it reads 858 backwards too.