The number 15225
15225 is a triangular number: 1 + 2 + … + 174 = 15225. Its prime factorisation is 3 × × 7 × 29. Divisors (24): 1, 3, 5, 7, 15, 21, 25, 29, 35, 75, 87, 105, 145, 175, 203, 435 … 15225.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 15225: a triangular number: 1 + 2 + … + 174 = 15225; a Harshad number: divisible by its digit sum 15.
- 2
15225 is composite. Its prime factorisation is
- 3
The divisors add up to 29760; without 15225 itself that is 14535, so 15225 is deficient (14535 is less than 15225). Euler's totient φ(15225) = 6720 numbers up to 15225 share no factor with it.
- 4
The digits of 15225 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 84 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15225 = 3 \times 5^{2} \times 7 \times 29 \]15225 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 29760 |
| Euler totient φ(n) | 6720 |
| Square | 231800625 |
| Cube | 3529164515625 |
| Square root | 123.389627 (= 5√609) |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 84 |
| Scientific notation | 1.5225 × |
15225 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand two hundred and twenty-five |
| Binary (base 2) | 11101101111001 |
| Octal (base 8) | 35571 |
| Hexadecimal (base 16) | 3B79 |
| Base 3 | 202212220 |
| As time | 15225 seconds = 4 h 13 min 45 s |
Is 15225 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 (15225 ÷ 3 = 5075) | 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 (15225 ÷ 5 = 3045) | 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 (15225 ÷ 7 = 2175) | 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 | No (remainder 6) | 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 1) | 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 15225 a prime number?
No. 15225 = 3 × × 7 × 29, so it is divisible by 3.
What are the factors of 15225?
1, 3, 5, 7, 15, 21, 25, 29, 35, 75, 87, 105, 145, 175, 203, 435, 525, 609, 725, 1015, 2175, 3045, 5075, 15225.
What is 15225 in binary?
11101101111001 (hexadecimal 3B79, octal 35571).
What is the square root of 15225?
About 123.3896, exactly 5√609.
Is 15225 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 15225?
15225 is a triangular number: 1 + 2 + … + 174 = 15225; a Harshad number: divisible by its digit sum 15.