The number 39680
39680 is a composite number with 36 divisors. Its prime factorisation is × 5 × 31. Divisors (36): 1, 2, 4, 5, 8, 10, 16, 20, 31, 32, 40, 62, 64, 80, 124, 128 … 39680.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 39680: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
39680 is composite. Its prime factorisation is
- 3
The divisors add up to 98112; without 39680 itself that is 58432, so 39680 is abundant (58432 is more than 39680). Euler's totient φ(39680) = 15360 numbers up to 39680 share no factor with it.
- 4
The digits of 39680 add up to 26, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 93 steps to reach 1.
LaTeX source of the formulas on this page
\[ 39680 = 2^{8} \times 5 \times 31 \]39680 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 36 |
| Sum of divisors | 98112 |
| Euler totient φ(n) | 15360 |
| Square | 1574502400 |
| Cube | 62476255232000 |
| Square root | 199.198394 (= 16√155) |
| Digit sum / digital root | 26 / 8 |
| Collatz steps to 1 | 93 |
| Scientific notation | 3.968 × |
39680 in other forms
| Form | Value |
|---|---|
| In words | thirty-nine thousand six hundred and eighty |
| Binary (base 2) | 1001101100000000 |
| Octal (base 8) | 115400 |
| Hexadecimal (base 16) | 9B00 |
| Base 3 | 2000102122 |
| As time | 39680 seconds = 11 h 1 min 20 s |
Is 39680 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (39680 ÷ 2 = 19840) | 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 (39680 ÷ 4 = 9920) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (39680 ÷ 5 = 7936) | 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 (39680 ÷ 8 = 4960) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (39680 ÷ 10 = 3968) | 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 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 39680 a prime number?
No. 39680 = × 5 × 31, so it is divisible by 2.
What are the factors of 39680?
1, 2, 4, 5, 8, 10, 16, 20, 31, 32, 40, 62, 64, 80, 124, 128, 155, 160, 248, 256, 310, 320, 496, 620, 640, 992, 1240, 1280, 1984, 2480, 3968, 4960, 7936, 9920, 19840, 39680.
What is 39680 in binary?
1001101100000000 (hexadecimal 9B00, octal 115400).
What is the square root of 39680?
About 199.1984, exactly 16√155.
Is 39680 divisible by 3?
No. Its digits add up to 26, which is not a multiple of 3.
What is special about the number 39680?
39680 is a happy number: repeatedly adding the squares of its digits reaches 1.