The number 71391
71391 is a composite number with 8 divisors. Its prime factorisation is 3 × 53 × 449. Divisors (8): 1, 3, 53, 159, 449, 1347, 23797, 71391.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
71391 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
71391 is composite. Its prime factorisation is
- 3
The divisors add up to 97200; without 71391 itself that is 25809, so 71391 is deficient (25809 is less than 71391). Euler's totient φ(71391) = 46592 numbers up to 71391 share no factor with it.
- 4
The digits of 71391 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 125 steps to reach 1.
LaTeX source of the formulas on this page
\[ 71391 = 3 \times 53 \times 449 \]
71391 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 97200 |
| Euler totient φ(n) | 46592 |
| Square | 5096674881 |
| Cube | 363856716429471 |
| Square root | 267.190943 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 125 |
| Scientific notation | 7.1391 × |
71391 in other forms
| Form | Value |
|---|---|
| In words | seventy-one thousand three hundred and ninety-one |
| Binary (base 2) | 10001011011011111 |
| Octal (base 8) | 213337 |
| Hexadecimal (base 16) | 116DF |
| Base 3 | 10121221010 |
| As time | 71391 seconds = 19 h 49 min 51 s |
Is 71391 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 | Yes (71391 ÷ 3 = 23797) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 3) | 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 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 71391 a prime number?
No. 71391 = 3 × 53 × 449, so it is divisible by 3.
What are the factors of 71391?
1, 3, 53, 159, 449, 1347, 23797, 71391.
What is 71391 in binary?
10001011011011111 (hexadecimal 116DF, octal 213337).
What is the square root of 71391?
About 267.1909.
Is 71391 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 71391?
It is a composite number with 8 divisors.