The number 72109
72109 is the 7140th prime number. Its only divisors are 1 and 72109.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 72109: the 7140th prime number.
- 2
72109 is prime, so its only factors are 1 and 72109. It is the 7140th prime; the next prime is 72139 and the one before is 72103.
- 3
The divisors add up to 72110; without 72109 itself that is 1, so 72109 is deficient (1 is less than 72109). Euler's totient φ(72109) = 72108 numbers up to 72109 share no factor with it.
- 4
The digits of 72109 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 81 steps to reach 1.
72109 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 72110 |
| Euler totient φ(n) | 72108 |
| Square | 5199707881 |
| Cube | 374945735591029 |
| Square root | 268.531190 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 81 |
| Scientific notation | 7.2109 × |
72109 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand one hundred and nine |
| Binary (base 2) | 10001100110101101 |
| Octal (base 8) | 214655 |
| Hexadecimal (base 16) | 119AD |
| Base 3 | 10122220201 |
| As time | 72109 seconds = 20 h 1 min 49 s |
Is 72109 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 | No (remainder 4) | 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 2) | 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 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | 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 72109 a prime number?
Yes. 72109 is divisible only by 1 and itself.
What are the factors of 72109?
1, 72109.
What is 72109 in binary?
10001100110101101 (hexadecimal 119AD, octal 214655).
What is the square root of 72109?
About 268.5312.
Is 72109 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 72109?
72109 is the 7140th prime number.