The number 40005
40005 is a composite number with 24 divisors. Its prime factorisation is × 5 × 7 × 127. Divisors (24): 1, 3, 5, 7, 9, 15, 21, 35, 45, 63, 105, 127, 315, 381, 635, 889 … 40005.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 40005: a Harshad number: divisible by its digit sum 9.
- 2
40005 is composite. Its prime factorisation is
- 3
The divisors add up to 79872; without 40005 itself that is 39867, so 40005 is deficient (39867 is less than 40005). Euler's totient φ(40005) = 18144 numbers up to 40005 share no factor with it.
- 4
The digits of 40005 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 181 steps to reach 1.
LaTeX source of the formulas on this page
\[ 40005 = 3^{2} \times 5 \times 7 \times 127 \]40005 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 79872 |
| Euler totient φ(n) | 18144 |
| Square | 1600400025 |
| Cube | 64024003000125 |
| Square root | 200.012500 (= 3√4445) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 181 |
| Scientific notation | 4.0005 × |
40005 in other forms
| Form | Value |
|---|---|
| In words | forty thousand and five |
| Binary (base 2) | 1001110001000101 |
| Octal (base 8) | 116105 |
| Hexadecimal (base 16) | 9C45 |
| Base 3 | 2000212200 |
| As time | 40005 seconds = 11 h 6 min 45 s |
Is 40005 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 (40005 ÷ 3 = 13335) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (40005 ÷ 5 = 8001) | 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 (40005 ÷ 7 = 5715) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (40005 ÷ 9 = 4445) | 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 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 40005 a prime number?
No. 40005 = × 5 × 7 × 127, so it is divisible by 3.
What are the factors of 40005?
1, 3, 5, 7, 9, 15, 21, 35, 45, 63, 105, 127, 315, 381, 635, 889, 1143, 1905, 2667, 4445, 5715, 8001, 13335, 40005.
What is 40005 in binary?
1001110001000101 (hexadecimal 9C45, octal 116105).
What is the square root of 40005?
About 200.0125, exactly 3√4445.
Is 40005 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 40005?
40005 is a Harshad number: divisible by its digit sum 9.