The number 25440
25440 is a composite number with 48 divisors. Its prime factorisation is × 3 × 5 × 53. Divisors (48): 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40 … 25440.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 25440: a Harshad number: divisible by its digit sum 15.
- 2
25440 is composite. Its prime factorisation is
- 3
The divisors add up to 81648; without 25440 itself that is 56208, so 25440 is abundant (56208 is more than 25440). Euler's totient φ(25440) = 6656 numbers up to 25440 share no factor with it.
- 4
The digits of 25440 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 108 steps to reach 1.
LaTeX source of the formulas on this page
\[ 25440 = 2^{5} \times 3 \times 5 \times 53 \]25440 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 48 |
| Sum of divisors | 81648 |
| Euler totient φ(n) | 6656 |
| Square | 647193600 |
| Cube | 16464605184000 |
| Square root | 159.499216 (= 4√1590) |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 108 |
| Scientific notation | 2.544 × |
25440 in other forms
| Form | Value |
|---|---|
| In words | twenty-five thousand four hundred and forty |
| Binary (base 2) | 110001101100000 |
| Octal (base 8) | 61540 |
| Hexadecimal (base 16) | 6360 |
| Base 3 | 1021220020 |
| As time | 25440 seconds = 7 h 4 min 0 s |
Is 25440 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (25440 ÷ 2 = 12720) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (25440 ÷ 3 = 8480) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (25440 ÷ 4 = 6360) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (25440 ÷ 5 = 5088) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (25440 ÷ 6 = 4240) | 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 | Yes (25440 ÷ 8 = 3180) | 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 | Yes (25440 ÷ 10 = 2544) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (25440 ÷ 12 = 2120) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 25440 a prime number?
No. 25440 = × 3 × 5 × 53, so it is divisible by 2.
What are the factors of 25440?
1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 48, 53, 60, 80, 96, 106, 120, 159, 160, 212, 240, 265, 318, 424, 480, 530, 636, 795, 848, 1060, 1272, 1590, 1696, 2120, 2544, 3180, 4240, 5088, 6360, 8480, 12720, 25440.
What is 25440 in binary?
110001101100000 (hexadecimal 6360, octal 61540).
What is the square root of 25440?
About 159.4992, exactly 4√1590.
Is 25440 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 25440?
25440 is a Harshad number: divisible by its digit sum 15.