The number 871
871 is a composite number with 4 divisors. Its prime factorisation is 13 × 67. Divisors (4): 1, 13, 67, 871.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 871: a semiprime: 13 × 67, the product of two primes.
- 2
871 is composite. Its prime factorisation is
- 3
The divisors add up to 952; without 871 itself that is 81, so 871 is deficient (81 is less than 871). Euler's totient φ(871) = 792 numbers up to 871 share no factor with it.
- 4
The digits of 871 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 178 steps to reach 1.
LaTeX source of the formulas on this page
\[ 871 = 13 \times 67 \]
871 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 952 |
| Euler totient φ(n) | 792 |
| Square | 758641 |
| Cube | 660776311 |
| Square root | 29.512709 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 178 |
| Scientific notation | 8.71 × |
871 in other forms
| Form | Value |
|---|---|
| In words | eight hundred and seventy-one |
| Roman numerals | DCCCLXXI |
| Binary (base 2) | 1101100111 |
| Octal (base 8) | 1547 |
| Hexadecimal (base 16) | 367 |
| Base 3 | 1012021 |
| As time | 871 seconds = 14 min 31 s |
Is 871 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 871 a prime number?
No. 871 = 13 × 67, so it is divisible by 13.
What are the factors of 871?
1, 13, 67, 871.
What is 871 in binary?
1101100111 (hexadecimal 367, octal 1547).
What is the square root of 871?
About 29.5127.
What is 871 in Roman numerals?
DCCCLXXI.
Is 871 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 871?
871 is a semiprime: 13 × 67, the product of two primes.