The number 40728
40728 is a composite number with 16 divisors. Its prime factorisation is × 3 × 1697. Divisors (16): 1, 2, 3, 4, 6, 8, 12, 24, 1697, 3394, 5091, 6788, 10182, 13576, 20364, 40728.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 40728: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
40728 is composite. Its prime factorisation is
- 3
The divisors add up to 101880; without 40728 itself that is 61152, so 40728 is abundant (61152 is more than 40728). Euler's totient φ(40728) = 13568 numbers up to 40728 share no factor with it.
- 4
The digits of 40728 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 44 steps to reach 1.
LaTeX source of the formulas on this page
\[ 40728 = 2^{3} \times 3 \times 1697 \]40728 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 101880 |
| Euler totient φ(n) | 13568 |
| Square | 1658769984 |
| Cube | 67558383908352 |
| Square root | 201.811794 (= 2√10182) |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 44 |
| Scientific notation | 4.0728 × |
40728 in other forms
| Form | Value |
|---|---|
| In words | forty thousand seven hundred and twenty-eight |
| Binary (base 2) | 1001111100011000 |
| Octal (base 8) | 117430 |
| Hexadecimal (base 16) | 9F18 |
| Base 3 | 2001212110 |
| As time | 40728 seconds = 11 h 18 min 48 s |
Is 40728 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (40728 ÷ 2 = 20364) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (40728 ÷ 3 = 13576) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (40728 ÷ 4 = 10182) | 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 | Yes (40728 ÷ 6 = 6788) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 (40728 ÷ 8 = 5091) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | 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 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (40728 ÷ 12 = 3394) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 40728 a prime number?
No. 40728 = × 3 × 1697, so it is divisible by 2.
What are the factors of 40728?
1, 2, 3, 4, 6, 8, 12, 24, 1697, 3394, 5091, 6788, 10182, 13576, 20364, 40728.
What is 40728 in binary?
1001111100011000 (hexadecimal 9F18, octal 117430).
What is the square root of 40728?
About 201.8118, exactly 2√10182.
Is 40728 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 40728?
40728 is a happy number: repeatedly adding the squares of its digits reaches 1.