The number 72005
72005 is a composite number with 4 divisors. Its prime factorisation is 5 × 14401. Divisors (4): 1, 5, 14401, 72005.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 72005: a semiprime: 5 × 14401, the product of two primes.
- 2
72005 is composite. Its prime factorisation is
- 3
The divisors add up to 86412; without 72005 itself that is 14407, so 72005 is deficient (14407 is less than 72005). Euler's totient φ(72005) = 57600 numbers up to 72005 share no factor with it.
- 4
The digits of 72005 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 143 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72005 = 5 \times 14401 \]
72005 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 86412 |
| Euler totient φ(n) | 57600 |
| Square | 5184720025 |
| Cube | 373325765400125 |
| Square root | 268.337474 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 143 |
| Scientific notation | 7.2005 × |
72005 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand and five |
| Binary (base 2) | 10001100101000101 |
| Octal (base 8) | 214505 |
| Hexadecimal (base 16) | 11945 |
| Base 3 | 10122202212 |
| As time | 72005 seconds = 20 h 0 min 5 s |
Is 72005 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 2) | 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 (72005 ÷ 5 = 14401) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 5) | 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 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 72005 a prime number?
No. 72005 = 5 × 14401, so it is divisible by 5.
What are the factors of 72005?
1, 5, 14401, 72005.
What is 72005 in binary?
10001100101000101 (hexadecimal 11945, octal 214505).
What is the square root of 72005?
About 268.3375.
Is 72005 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 72005?
72005 is a semiprime: 5 × 14401, the product of two primes.