The number 38991
38991 is a composite number with 8 divisors. Its prime factorisation is 3 × 41 × 317. Divisors (8): 1, 3, 41, 123, 317, 951, 12997, 38991.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 38991: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
38991 is composite. Its prime factorisation is
- 3
The divisors add up to 53424; without 38991 itself that is 14433, so 38991 is deficient (14433 is less than 38991). Euler's totient φ(38991) = 25280 numbers up to 38991 share no factor with it.
- 4
The digits of 38991 add up to 30, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 124 steps to reach 1.
LaTeX source of the formulas on this page
\[ 38991 = 3 \times 41 \times 317 \]
38991 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 53424 |
| Euler totient φ(n) | 25280 |
| Square | 1520298081 |
| Cube | 59277942476271 |
| Square root | 197.461389 |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 124 |
| Scientific notation | 3.8991 × |
38991 in other forms
| Form | Value |
|---|---|
| In words | thirty-eight thousand nine hundred and ninety-one |
| Binary (base 2) | 1001100001001111 |
| Octal (base 8) | 114117 |
| Hexadecimal (base 16) | 984F |
| Base 3 | 1222111010 |
| As time | 38991 seconds = 10 h 49 min 51 s |
Is 38991 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 | Yes (38991 ÷ 3 = 12997) | 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 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | 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 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 38991 a prime number?
No. 38991 = 3 × 41 × 317, so it is divisible by 3.
What are the factors of 38991?
1, 3, 41, 123, 317, 951, 12997, 38991.
What is 38991 in binary?
1001100001001111 (hexadecimal 984F, octal 114117).
What is the square root of 38991?
About 197.4614.
Is 38991 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 38991?
38991 is a happy number: repeatedly adding the squares of its digits reaches 1.