The number 25425
25425 is a triangular number: 1 + 2 + … + 225 = 25425. Its prime factorisation is × × 113. Divisors (18): 1, 3, 5, 9, 15, 25, 45, 75, 113, 225, 339, 565, 1017, 1695, 2825, 5085 … 25425.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 25425: a triangular number: 1 + 2 + … + 225 = 25425.
- 2
25425 is composite. Its prime factorisation is
- 3
The divisors add up to 45942; without 25425 itself that is 20517, so 25425 is deficient (20517 is less than 25425). Euler's totient φ(25425) = 13440 numbers up to 25425 share no factor with it.
- 4
The digits of 25425 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 108 steps to reach 1.
LaTeX source of the formulas on this page
\[ 25425 = 3^{2} \times 5^{2} \times 113 \]25425 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 18 |
| Sum of divisors | 45942 |
| Euler totient φ(n) | 13440 |
| Square | 646430625 |
| Cube | 16435498640625 |
| Square root | 159.452187 (= 15√113) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 108 |
| Scientific notation | 2.5425 × |
25425 in other forms
| Form | Value |
|---|---|
| In words | twenty-five thousand four hundred and twenty-five |
| Binary (base 2) | 110001101010001 |
| Octal (base 8) | 61521 |
| Hexadecimal (base 16) | 6351 |
| Base 3 | 1021212200 |
| As time | 25425 seconds = 7 h 3 min 45 s |
Is 25425 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 (25425 ÷ 3 = 8475) | 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 (25425 ÷ 5 = 5085) | 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 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (25425 ÷ 9 = 2825) | 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 4) | 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 25425 a prime number?
No. 25425 = × × 113, so it is divisible by 3.
What are the factors of 25425?
1, 3, 5, 9, 15, 25, 45, 75, 113, 225, 339, 565, 1017, 1695, 2825, 5085, 8475, 25425.
What is 25425 in binary?
110001101010001 (hexadecimal 6351, octal 61521).
What is the square root of 25425?
About 159.4522, exactly 15√113.
Is 25425 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 25425?
25425 is a triangular number: 1 + 2 + … + 225 = 25425.