The number 61425
61425 is a triangular number: 1 + 2 + … + 350 = 61425. Its prime factorisation is × × 7 × 13. Divisors (48): 1, 3, 5, 7, 9, 13, 15, 21, 25, 27, 35, 39, 45, 63, 65, 75 … 61425.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 61425: a triangular number: 1 + 2 + … + 350 = 61425; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
61425 is composite. Its prime factorisation is
- 3
The divisors add up to 138880; without 61425 itself that is 77455, so 61425 is abundant (77455 is more than 61425). Euler's totient φ(61425) = 25920 numbers up to 61425 share no factor with it.
- 4
The digits of 61425 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 135 steps to reach 1.
LaTeX source of the formulas on this page
\[ 61425 = 3^{3} \times 5^{2} \times 7 \times 13 \]61425 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 48 |
| Sum of divisors | 138880 |
| Euler totient φ(n) | 25920 |
| Square | 3773030625 |
| Cube | 231758406140625 |
| Square root | 247.840675 (= 15√273) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 135 |
| Scientific notation | 6.1425 × |
61425 in other forms
| Form | Value |
|---|---|
| In words | sixty-one thousand four hundred and twenty-five |
| Binary (base 2) | 1110111111110001 |
| Octal (base 8) | 167761 |
| Hexadecimal (base 16) | EFF1 |
| Base 3 | 10010021000 |
| As time | 61425 seconds = 17 h 3 min 45 s |
Is 61425 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 (61425 ÷ 3 = 20475) | 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 (61425 ÷ 5 = 12285) | 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 (61425 ÷ 7 = 8775) | 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 (61425 ÷ 9 = 6825) | 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 61425 a prime number?
No. 61425 = × × 7 × 13, so it is divisible by 3.
What are the factors of 61425?
1, 3, 5, 7, 9, 13, 15, 21, 25, 27, 35, 39, 45, 63, 65, 75, 91, 105, 117, 135, 175, 189, 195, 225, 273, 315, 325, 351, 455, 525, 585, 675, 819, 945, 975, 1365, 1575, 1755, 2275, 2457, 2925, 4095, 4725, 6825, 8775, 12285, 20475, 61425.
What is 61425 in binary?
1110111111110001 (hexadecimal EFF1, octal 167761).
What is the square root of 61425?
About 247.8407, exactly 15√273.
Is 61425 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 61425?
61425 is a triangular number: 1 + 2 + … + 350 = 61425; a happy number: repeatedly adding the squares of its digits reaches 1.