The number 38728
38728 is a composite number with 16 divisors. Its prime factorisation is × 47 × 103. Divisors (16): 1, 2, 4, 8, 47, 94, 103, 188, 206, 376, 412, 824, 4841, 9682, 19364, 38728.
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How to work it out
- 1
What is special about 38728: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
38728 is composite. Its prime factorisation is
- 3
The divisors add up to 74880; without 38728 itself that is 36152, so 38728 is deficient (36152 is less than 38728). Euler's totient φ(38728) = 18768 numbers up to 38728 share no factor with it.
- 4
The digits of 38728 add up to 28, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 106 steps to reach 1.
LaTeX source of the formulas on this page
\[ 38728 = 2^{3} \times 47 \times 103 \]38728 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 74880 |
| Euler totient φ(n) | 18768 |
| Square | 1499857984 |
| Cube | 58086500004352 |
| Square root | 196.794309 (= 2√9682) |
| Digit sum / digital root | 28 / 1 |
| Collatz steps to 1 | 106 |
| Scientific notation | 3.8728 × |
38728 in other forms
| Form | Value |
|---|---|
| In words | thirty-eight thousand seven hundred and twenty-eight |
| Binary (base 2) | 1001011101001000 |
| Octal (base 8) | 113510 |
| Hexadecimal (base 16) | 9748 |
| Base 3 | 1222010101 |
| As time | 38728 seconds = 10 h 45 min 28 s |
Is 38728 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (38728 ÷ 2 = 19364) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (38728 ÷ 4 = 9682) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 (38728 ÷ 8 = 4841) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 38728 a prime number?
No. 38728 = × 47 × 103, so it is divisible by 2.
What are the factors of 38728?
1, 2, 4, 8, 47, 94, 103, 188, 206, 376, 412, 824, 4841, 9682, 19364, 38728.
What is 38728 in binary?
1001011101001000 (hexadecimal 9748, octal 113510).
What is the square root of 38728?
About 196.7943, exactly 2√9682.
Is 38728 divisible by 3?
No. Its digits add up to 28, which is not a multiple of 3.
What is special about the number 38728?
38728 is a happy number: repeatedly adding the squares of its digits reaches 1.