The number 72225
72225 is a composite number with 24 divisors. Its prime factorisation is × × 107. Divisors (24): 1, 3, 5, 9, 15, 25, 27, 45, 75, 107, 135, 225, 321, 535, 675, 963 … 72225.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 72225: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
72225 is composite. Its prime factorisation is
- 3
The divisors add up to 133920; without 72225 itself that is 61695, so 72225 is deficient (61695 is less than 72225). Euler's totient φ(72225) = 38160 numbers up to 72225 share no factor with it.
- 4
The digits of 72225 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 187 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72225 = 3^{3} \times 5^{2} \times 107 \]72225 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 133920 |
| Euler totient φ(n) | 38160 |
| Square | 5216450625 |
| Cube | 376758146390625 |
| Square root | 268.747093 (= 15√321) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 187 |
| Scientific notation | 7.2225 × |
72225 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand two hundred and twenty-five |
| Binary (base 2) | 10001101000100001 |
| Octal (base 8) | 215041 |
| Hexadecimal (base 16) | 11A21 |
| Base 3 | 10200002000 |
| As time | 72225 seconds = 20 h 3 min 45 s |
Is 72225 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 (72225 ÷ 3 = 24075) | 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 (72225 ÷ 5 = 14445) | 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 | No (remainder 6) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (72225 ÷ 9 = 8025) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 72225 a prime number?
No. 72225 = × × 107, so it is divisible by 3.
What are the factors of 72225?
1, 3, 5, 9, 15, 25, 27, 45, 75, 107, 135, 225, 321, 535, 675, 963, 1605, 2675, 2889, 4815, 8025, 14445, 24075, 72225.
What is 72225 in binary?
10001101000100001 (hexadecimal 11A21, octal 215041).
What is the square root of 72225?
About 268.7471, exactly 15√321.
Is 72225 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 72225?
72225 is a happy number: repeatedly adding the squares of its digits reaches 1.