The number 31487
31487 is a composite number with 6 divisors. Its prime factorisation is 23 Ć . Divisors (6): 1, 23, 37, 851, 1369, 31487.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31487: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 23.
- 2
31487 is composite. Its prime factorisation is
- 3
The divisors add up to 33768; without 31487 itself that is 2281, so 31487 is deficient (2281 is less than 31487). Euler's totient Ļ(31487) = 29304 numbers up to 31487 share no factor with it.
- 4
The digits of 31487 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 85 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31487 = 23 \times 37^{2} \]31487 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 33768 |
| Euler totient Ļ(n) | 29304 |
| Square | 991431169 |
| Cube | 31217193218303 |
| Square root | 177.445766 (= 37ā23) |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 85 |
| Scientific notation | 3.1487 Ć |
31487 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand four hundred and eighty-seven |
| Binary (base 2) | 111101011111111 |
| Octal (base 8) | 75377 |
| Hexadecimal (base 16) | 7AFF |
| Base 3 | 1121012012 |
| As time | 31487 seconds = 8 h 44 min 47 s |
Is 31487 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 2) | 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 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 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 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | 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 31487 a prime number?
No. 31487 = 23 Ć , so it is divisible by 23.
What are the factors of 31487?
1, 23, 37, 851, 1369, 31487.
What is 31487 in binary?
111101011111111 (hexadecimal 7AFF, octal 75377).
What is the square root of 31487?
About 177.4458, exactly 37ā23.
Is 31487 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 31487?
31487 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 23.