The number 31087
31087 is a composite number with 4 divisors. Its prime factorisation is 7 × 4441. Divisors (4): 1, 7, 4441, 31087.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31087: a semiprime: 7 × 4441, the product of two primes.
- 2
31087 is composite. Its prime factorisation is
- 3
The divisors add up to 35536; without 31087 itself that is 4449, so 31087 is deficient (4449 is less than 31087). Euler's totient φ(31087) = 26640 numbers up to 31087 share no factor with it.
- 4
The digits of 31087 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 116 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31087 = 7 \times 4441 \]
31087 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 35536 |
| Euler totient φ(n) | 26640 |
| Square | 966401569 |
| Cube | 30042525575503 |
| Square root | 176.315059 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 116 |
| Scientific notation | 3.1087 × |
31087 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand and eighty-seven |
| Binary (base 2) | 111100101101111 |
| Octal (base 8) | 74557 |
| Hexadecimal (base 16) | 796F |
| Base 3 | 1120122101 |
| As time | 31087 seconds = 8 h 38 min 7 s |
Is 31087 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 2) | 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 | Yes (31087 ÷ 7 = 4441) | 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 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31087 a prime number?
No. 31087 = 7 × 4441, so it is divisible by 7.
What are the factors of 31087?
1, 7, 4441, 31087.
What is 31087 in binary?
111100101101111 (hexadecimal 796F, octal 74557).
What is the square root of 31087?
About 176.3151.
Is 31087 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 31087?
31087 is a semiprime: 7 × 4441, the product of two primes.