The number 671
671 is a composite number with 4 divisors. Its prime factorisation is 11 × 61. Divisors (4): 1, 11, 61, 671.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 671: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 11 × 61, the product of two primes.
- 2
671 is composite. Its prime factorisation is
- 3
The divisors add up to 744; without 671 itself that is 73, so 671 is deficient (73 is less than 671). Euler's totient φ(671) = 600 numbers up to 671 share no factor with it.
- 4
The digits of 671 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 95 steps to reach 1.
LaTeX source of the formulas on this page
\[ 671 = 11 \times 61 \]
671 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 744 |
| Euler totient φ(n) | 600 |
| Square | 450241 |
| Cube | 302111711 |
| Square root | 25.903668 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 95 |
| Scientific notation | 6.71 × |
671 in other forms
| Form | Value |
|---|---|
| In words | six hundred and seventy-one |
| Roman numerals | DCLXXI |
| Binary (base 2) | 1010011111 |
| Octal (base 8) | 1237 |
| Hexadecimal (base 16) | 29F |
| Base 3 | 220212 |
| As time | 671 seconds = 11 min 11 s |
Is 671 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 2) | 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 5) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | 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 | Yes (671 ÷ 11 = 61) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 671 a prime number?
No. 671 = 11 × 61, so it is divisible by 11.
What are the factors of 671?
1, 11, 61, 671.
What is 671 in binary?
1010011111 (hexadecimal 29F, octal 1237).
What is the square root of 671?
About 25.9037.
What is 671 in Roman numerals?
DCLXXI.
Is 671 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 671?
671 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 11 × 61, the product of two primes.