The number 31395
31395 is a composite number with 32 divisors. Its prime factorisation is 3 × 5 × 7 × 13 × 23. Divisors (32): 1, 3, 5, 7, 13, 15, 21, 23, 35, 39, 65, 69, 91, 105, 115, 161 … 31395.
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How to work it out
- 1
What is special about 31395: a Harshad number: divisible by its digit sum 21.
- 2
31395 is composite. Its prime factorisation is
- 3
The divisors add up to 64512; without 31395 itself that is 33117, so 31395 is abundant (33117 is more than 31395). Euler's totient φ(31395) = 12672 numbers up to 31395 share no factor with it.
- 4
The digits of 31395 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 178 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31395 = 3 \times 5 \times 7 \times 13 \times 23 \]
31395 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 64512 |
| Euler totient φ(n) | 12672 |
| Square | 985646025 |
| Cube | 30944356954875 |
| Square root | 177.186343 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 178 |
| Scientific notation | 3.1395 × |
31395 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand three hundred and ninety-five |
| Binary (base 2) | 111101010100011 |
| Octal (base 8) | 75243 |
| Hexadecimal (base 16) | 7AA3 |
| Base 3 | 1121001210 |
| As time | 31395 seconds = 8 h 43 min 15 s |
Is 31395 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 (31395 ÷ 3 = 10465) | 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 (31395 ÷ 5 = 6279) | 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 | Yes (31395 ÷ 7 = 4485) | 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 | No (remainder 3) | 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 1) | 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 31395 a prime number?
No. 31395 = 3 × 5 × 7 × 13 × 23, so it is divisible by 3.
What are the factors of 31395?
1, 3, 5, 7, 13, 15, 21, 23, 35, 39, 65, 69, 91, 105, 115, 161, 195, 273, 299, 345, 455, 483, 805, 897, 1365, 1495, 2093, 2415, 4485, 6279, 10465, 31395.
What is 31395 in binary?
111101010100011 (hexadecimal 7AA3, octal 75243).
What is the square root of 31395?
About 177.1863.
Is 31395 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 31395?
31395 is a Harshad number: divisible by its digit sum 21.