The number 8240
8240 is a composite number with 20 divisors. Its prime factorisation is × 5 × 103. Divisors (20): 1, 2, 4, 5, 8, 10, 16, 20, 40, 80, 103, 206, 412, 515, 824, 1030 … 8240.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
8240 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
8240 is composite. Its prime factorisation is
- 3
The divisors add up to 19344; without 8240 itself that is 11104, so 8240 is abundant (11104 is more than 8240). Euler's totient φ(8240) = 3264 numbers up to 8240 share no factor with it.
- 4
The digits of 8240 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 127 steps to reach 1.
LaTeX source of the formulas on this page
\[ 8240 = 2^{4} \times 5 \times 103 \]8240 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 19344 |
| Euler totient φ(n) | 3264 |
| Square | 67897600 |
| Cube | 559476224000 |
| Square root | 90.774446 (= 4√515) |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 127 |
| Scientific notation | 8.24 × |
8240 in other forms
| Form | Value |
|---|---|
| In words | eight thousand two hundred and forty |
| Binary (base 2) | 10000000110000 |
| Octal (base 8) | 20060 |
| Hexadecimal (base 16) | 2030 |
| Base 3 | 102022012 |
| As time | 8240 seconds = 2 h 17 min 20 s |
Is 8240 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (8240 ÷ 2 = 4120) | 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 (8240 ÷ 4 = 2060) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (8240 ÷ 5 = 1648) | 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 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 (8240 ÷ 8 = 1030) | 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 (8240 ÷ 10 = 824) | 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 8240 a prime number?
No. 8240 = × 5 × 103, so it is divisible by 2.
What are the factors of 8240?
1, 2, 4, 5, 8, 10, 16, 20, 40, 80, 103, 206, 412, 515, 824, 1030, 1648, 2060, 4120, 8240.
What is 8240 in binary?
10000000110000 (hexadecimal 2030, octal 20060).
What is the square root of 8240?
About 90.7744, exactly 4√515.
Is 8240 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 8240?
It is a composite number with 20 divisors.