The number 40405
40405 is a composite number with 4 divisors. Its prime factorisation is 5 × 8081. Divisors (4): 1, 5, 8081, 40405.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 40405: a semiprime: 5 × 8081, the product of two primes.
- 2
40405 is composite. Its prime factorisation is
- 3
The divisors add up to 48492; without 40405 itself that is 8087, so 40405 is deficient (8087 is less than 40405). Euler's totient φ(40405) = 32320 numbers up to 40405 share no factor with it.
- 4
The digits of 40405 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 44 steps to reach 1.
LaTeX source of the formulas on this page
\[ 40405 = 5 \times 8081 \]
40405 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 48492 |
| Euler totient φ(n) | 32320 |
| Square | 1632564025 |
| Cube | 65963749430125 |
| Square root | 201.009950 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 44 |
| Scientific notation | 4.0405 × |
40405 in other forms
| Form | Value |
|---|---|
| In words | forty thousand four hundred and five |
| Binary (base 2) | 1001110111010101 |
| Octal (base 8) | 116725 |
| Hexadecimal (base 16) | 9DD5 |
| Base 3 | 2001102111 |
| As time | 40405 seconds = 11 h 13 min 25 s |
Is 40405 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 | No (remainder 1) | 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 (40405 ÷ 5 = 8081) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 40405 a prime number?
No. 40405 = 5 × 8081, so it is divisible by 5.
What are the factors of 40405?
1, 5, 8081, 40405.
What is 40405 in binary?
1001110111010101 (hexadecimal 9DD5, octal 116725).
What is the square root of 40405?
About 201.0100.
Is 40405 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 40405?
40405 is a semiprime: 5 × 8081, the product of two primes.