The number 31284
31284 is a composite number with 36 divisors. Its prime factorisation is × × 11 × 79. Divisors (36): 1, 2, 3, 4, 6, 9, 11, 12, 18, 22, 33, 36, 44, 66, 79, 99 … 31284.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31284: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.
- 2
31284 is composite. Its prime factorisation is
- 3
The divisors add up to 87360; without 31284 itself that is 56076, so 31284 is abundant (56076 is more than 31284). Euler's totient φ(31284) = 9360 numbers up to 31284 share no factor with it.
- 4
The digits of 31284 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 103 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31284 = 2^{2} \times 3^{2} \times 11 \times 79 \]31284 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 36 |
| Sum of divisors | 87360 |
| Euler totient φ(n) | 9360 |
| Square | 978688656 |
| Cube | 30617295914304 |
| Square root | 176.872836 (= 6√869) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 103 |
| Scientific notation | 3.1284 × |
31284 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand two hundred and eighty-four |
| Binary (base 2) | 111101000110100 |
| Octal (base 8) | 75064 |
| Hexadecimal (base 16) | 7A34 |
| Base 3 | 1120220200 |
| As time | 31284 seconds = 8 h 41 min 24 s |
Is 31284 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31284 ÷ 2 = 15642) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (31284 ÷ 3 = 10428) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (31284 ÷ 4 = 7821) | 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 | Yes (31284 ÷ 6 = 5214) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (31284 ÷ 9 = 3476) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (31284 ÷ 11 = 2844) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (31284 ÷ 12 = 2607) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31284 a prime number?
No. 31284 = × × 11 × 79, so it is divisible by 2.
What are the factors of 31284?
1, 2, 3, 4, 6, 9, 11, 12, 18, 22, 33, 36, 44, 66, 79, 99, 132, 158, 198, 237, 316, 396, 474, 711, 869, 948, 1422, 1738, 2607, 2844, 3476, 5214, 7821, 10428, 15642, 31284.
What is 31284 in binary?
111101000110100 (hexadecimal 7A34, octal 75064).
What is the square root of 31284?
About 176.8728, exactly 6√869.
Is 31284 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 31284?
31284 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.