The number 87440
87440 is a composite number with 20 divisors. Its prime factorisation is × 5 × 1093. Divisors (20): 1, 2, 4, 5, 8, 10, 16, 20, 40, 80, 1093, 2186, 4372, 5465, 8744, 10930 … 87440.
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How to work it out
- 1
87440 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
87440 is composite. Its prime factorisation is
- 3
The divisors add up to 203484; without 87440 itself that is 116044, so 87440 is abundant (116044 is more than 87440). Euler's totient φ(87440) = 34944 numbers up to 87440 share no factor with it.
- 4
The digits of 87440 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 164 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87440 = 2^{4} \times 5 \times 1093 \]87440 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 203484 |
| Euler totient φ(n) | 34944 |
| Square | 7645753600 |
| Cube | 668544694784000 |
| Square root | 295.702553 (= 4√5465) |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 164 |
| Scientific notation | 8.744 × |
87440 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand four hundred and forty |
| Binary (base 2) | 10101010110010000 |
| Octal (base 8) | 252620 |
| Hexadecimal (base 16) | 15590 |
| Base 3 | 11102221112 |
| As time | 87440 seconds = 24 h 17 min 20 s |
Is 87440 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (87440 ÷ 2 = 43720) | 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 (87440 ÷ 4 = 21860) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (87440 ÷ 5 = 17488) | 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 3) | 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 (87440 ÷ 8 = 10930) | 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 (87440 ÷ 10 = 8744) | 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 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 87440 a prime number?
No. 87440 = × 5 × 1093, so it is divisible by 2.
What are the factors of 87440?
1, 2, 4, 5, 8, 10, 16, 20, 40, 80, 1093, 2186, 4372, 5465, 8744, 10930, 17488, 21860, 43720, 87440.
What is 87440 in binary?
10101010110010000 (hexadecimal 15590, octal 252620).
What is the square root of 87440?
About 295.7026, exactly 4√5465.
Is 87440 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 87440?
It is a composite number with 20 divisors.