The number 31291
31291 is a composite number with 8 divisors. Its prime factorisation is 13 × 29 × 83. Divisors (8): 1, 13, 29, 83, 377, 1079, 2407, 31291.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31291 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31291 is composite. Its prime factorisation is
- 3
The divisors add up to 35280; without 31291 itself that is 3989, so 31291 is deficient (3989 is less than 31291). Euler's totient φ(31291) = 27552 numbers up to 31291 share no factor with it.
- 4
The digits of 31291 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 85 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31291 = 13 \times 29 \times 83 \]
31291 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 35280 |
| Euler totient φ(n) | 27552 |
| Square | 979126681 |
| Cube | 30637852975171 |
| Square root | 176.892623 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 85 |
| Scientific notation | 3.1291 × |
31291 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand two hundred and ninety-one |
| Binary (base 2) | 111101000111011 |
| Octal (base 8) | 75073 |
| Hexadecimal (base 16) | 7A3B |
| Base 3 | 1120220221 |
| As time | 31291 seconds = 8 h 41 min 31 s |
Is 31291 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 1) | 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 3) | 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 7) | 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 31291 a prime number?
No. 31291 = 13 × 29 × 83, so it is divisible by 13.
What are the factors of 31291?
1, 13, 29, 83, 377, 1079, 2407, 31291.
What is 31291 in binary?
111101000111011 (hexadecimal 7A3B, octal 75073).
What is the square root of 31291?
About 176.8926.
Is 31291 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 31291?
It is a composite number with 8 divisors.