The number 31228
31228 is a composite number with 12 divisors. Its prime factorisation is × 37 × 211. Divisors (12): 1, 2, 4, 37, 74, 148, 211, 422, 844, 7807, 15614, 31228.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31228: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
31228 is composite. Its prime factorisation is
- 3
The divisors add up to 56392; without 31228 itself that is 25164, so 31228 is deficient (25164 is less than 31228). Euler's totient φ(31228) = 15120 numbers up to 31228 share no factor with it.
- 4
The digits of 31228 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
\[ 31228 = 2^{2} \times 37 \times 211 \]31228 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 56392 |
| Euler totient φ(n) | 15120 |
| Square | 975187984 |
| Cube | 30453170364352 |
| Square root | 176.714459 (= 2√7807) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 85 |
| Scientific notation | 3.1228 × |
31228 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand two hundred and twenty-eight |
| Binary (base 2) | 111100111111100 |
| Octal (base 8) | 74774 |
| Hexadecimal (base 16) | 79FC |
| Base 3 | 1120211121 |
| As time | 31228 seconds = 8 h 40 min 28 s |
Is 31228 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31228 ÷ 2 = 15614) | 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 | Yes (31228 ÷ 4 = 7807) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31228 a prime number?
No. 31228 = × 37 × 211, so it is divisible by 2.
What are the factors of 31228?
1, 2, 4, 37, 74, 148, 211, 422, 844, 7807, 15614, 31228.
What is 31228 in binary?
111100111111100 (hexadecimal 79FC, octal 74774).
What is the square root of 31228?
About 176.7145, exactly 2√7807.
Is 31228 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 31228?
31228 is a happy number: repeatedly adding the squares of its digits reaches 1.