The number 31889
31889 is a composite number with 8 divisors. Its prime factorisation is 11 × 13 × 223. Divisors (8): 1, 11, 13, 143, 223, 2453, 2899, 31889.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31889: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
31889 is composite. Its prime factorisation is
- 3
The divisors add up to 37632; without 31889 itself that is 5743, so 31889 is deficient (5743 is less than 31889). Euler's totient φ(31889) = 26640 numbers up to 31889 share no factor with it.
- 4
The digits of 31889 add up to 29, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 59 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31889 = 11 \times 13 \times 223 \]
31889 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 37632 |
| Euler totient φ(n) | 26640 |
| Square | 1016908321 |
| Cube | 32428189448369 |
| Square root | 178.574914 |
| Digit sum / digital root | 29 / 2 |
| Collatz steps to 1 | 59 |
| Scientific notation | 3.1889 × |
31889 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand eight hundred and eighty-nine |
| Binary (base 2) | 111110010010001 |
| Octal (base 8) | 76221 |
| Hexadecimal (base 16) | 7C91 |
| Base 3 | 1121202002 |
| As time | 31889 seconds = 8 h 51 min 29 s |
Is 31889 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 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | 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 4) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (31889 ÷ 11 = 2899) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31889 a prime number?
No. 31889 = 11 × 13 × 223, so it is divisible by 11.
What are the factors of 31889?
1, 11, 13, 143, 223, 2453, 2899, 31889.
What is 31889 in binary?
111110010010001 (hexadecimal 7C91, octal 76221).
What is the square root of 31889?
About 178.5749.
Is 31889 divisible by 3?
No. Its digits add up to 29, which is not a multiple of 3.
What is special about the number 31889?
31889 is a happy number: repeatedly adding the squares of its digits reaches 1.