The number 51440
51440 is a composite number with 20 divisors. Its prime factorisation is × 5 × 643. Divisors (20): 1, 2, 4, 5, 8, 10, 16, 20, 40, 80, 643, 1286, 2572, 3215, 5144, 6430 … 51440.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
51440 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
51440 is composite. Its prime factorisation is
- 3
The divisors add up to 119784; without 51440 itself that is 68344, so 51440 is abundant (68344 is more than 51440). Euler's totient φ(51440) = 20544 numbers up to 51440 share no factor with it.
- 4
The digits of 51440 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 171 steps to reach 1.
LaTeX source of the formulas on this page
\[ 51440 = 2^{4} \times 5 \times 643 \]51440 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 119784 |
| Euler totient φ(n) | 20544 |
| Square | 2646073600 |
| Cube | 136114025984000 |
| Square root | 226.803880 (= 4√3215) |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 171 |
| Scientific notation | 5.144 × |
51440 in other forms
| Form | Value |
|---|---|
| In words | fifty-one thousand four hundred and forty |
| Binary (base 2) | 1100100011110000 |
| Octal (base 8) | 144360 |
| Hexadecimal (base 16) | C8F0 |
| Base 3 | 2121120012 |
| As time | 51440 seconds = 14 h 17 min 20 s |
Is 51440 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (51440 ÷ 2 = 25720) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (51440 ÷ 4 = 12860) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (51440 ÷ 5 = 10288) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 (51440 ÷ 8 = 6430) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (51440 ÷ 10 = 5144) | 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 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 51440 a prime number?
No. 51440 = × 5 × 643, so it is divisible by 2.
What are the factors of 51440?
1, 2, 4, 5, 8, 10, 16, 20, 40, 80, 643, 1286, 2572, 3215, 5144, 6430, 10288, 12860, 25720, 51440.
What is 51440 in binary?
1100100011110000 (hexadecimal C8F0, octal 144360).
What is the square root of 51440?
About 226.8039, exactly 4√3215.
Is 51440 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 51440?
It is a composite number with 20 divisors.