The number 19440
19440 is a composite number with 60 divisors. Its prime factorisation is × × 5. Divisors (60): 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 27 … 19440.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 19440: a Harshad number: divisible by its digit sum 18.
- 2
19440 is composite. Its prime factorisation is
- 3
The divisors add up to 67704; without 19440 itself that is 48264, so 19440 is abundant (48264 is more than 19440). Euler's totient φ(19440) = 5184 numbers up to 19440 share no factor with it.
- 4
The digits of 19440 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 167 steps to reach 1.
LaTeX source of the formulas on this page
\[ 19440 = 2^{4} \times 3^{5} \times 5 \]19440 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 60 |
| Sum of divisors | 67704 |
| Euler totient φ(n) | 5184 |
| Square | 377913600 |
| Cube | 7346640384000 |
| Square root | 139.427400 (= 36√15) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 167 |
| Scientific notation | 1.944 × |
19440 in other forms
| Form | Value |
|---|---|
| In words | nineteen thousand four hundred and forty |
| Binary (base 2) | 100101111110000 |
| Octal (base 8) | 45760 |
| Hexadecimal (base 16) | 4BF0 |
| Base 3 | 222200000 |
| As time | 19440 seconds = 5 h 24 min 0 s |
Is 19440 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (19440 ÷ 2 = 9720) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (19440 ÷ 3 = 6480) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (19440 ÷ 4 = 4860) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (19440 ÷ 5 = 3888) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (19440 ÷ 6 = 3240) | 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 | Yes (19440 ÷ 8 = 2430) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (19440 ÷ 9 = 2160) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (19440 ÷ 10 = 1944) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (19440 ÷ 12 = 1620) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 19440 a prime number?
No. 19440 = × × 5, so it is divisible by 2.
What are the factors of 19440?
1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 27, 30, 36, 40, 45, 48, 54, 60, 72, 80, 81, 90, 108, 120, 135, 144, 162, 180, 216, 240, 243, 270, 324, 360, 405, 432, 486, 540, 648, 720, 810, 972, 1080, 1215, 1296, 1620, 1944, 2160, 2430, 3240, 3888, 4860, 6480, 9720, 19440.
What is 19440 in binary?
100101111110000 (hexadecimal 4BF0, octal 45760).
What is the square root of 19440?
About 139.4274, exactly 36√15.
Is 19440 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 19440?
19440 is a Harshad number: divisible by its digit sum 18.