The number 31995
31995 is a composite number with 20 divisors. Its prime factorisation is × 5 × 79. Divisors (20): 1, 3, 5, 9, 15, 27, 45, 79, 81, 135, 237, 395, 405, 711, 1185, 2133 … 31995.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31995: a Harshad number: divisible by its digit sum 27.
- 2
31995 is composite. Its prime factorisation is
- 3
The divisors add up to 58080; without 31995 itself that is 26085, so 31995 is deficient (26085 is less than 31995). Euler's totient φ(31995) = 16848 numbers up to 31995 share no factor with it.
- 4
The digits of 31995 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 98 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31995 = 3^{4} \times 5 \times 79 \]31995 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 58080 |
| Euler totient φ(n) | 16848 |
| Square | 1023680025 |
| Cube | 32752642399875 |
| Square root | 178.871462 (= 9√395) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 98 |
| Scientific notation | 3.1995 × |
31995 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred and ninety-five |
| Binary (base 2) | 111110011111011 |
| Octal (base 8) | 76373 |
| Hexadecimal (base 16) | 7CFB |
| Base 3 | 1121220000 |
| As time | 31995 seconds = 8 h 53 min 15 s |
Is 31995 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 (31995 ÷ 3 = 10665) | 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 | Yes (31995 ÷ 5 = 6399) | 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 5) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (31995 ÷ 9 = 3555) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | 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 31995 a prime number?
No. 31995 = × 5 × 79, so it is divisible by 3.
What are the factors of 31995?
1, 3, 5, 9, 15, 27, 45, 79, 81, 135, 237, 395, 405, 711, 1185, 2133, 3555, 6399, 10665, 31995.
What is 31995 in binary?
111110011111011 (hexadecimal 7CFB, octal 76373).
What is the square root of 31995?
About 178.8715, exactly 9√395.
Is 31995 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 31995?
31995 is a Harshad number: divisible by its digit sum 27.