The number 8742
8742 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 31 × 47. Divisors (16): 1, 2, 3, 6, 31, 47, 62, 93, 94, 141, 186, 282, 1457, 2914, 4371, 8742.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 8742: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
8742 is composite. Its prime factorisation is
- 3
The divisors add up to 18432; without 8742 itself that is 9690, so 8742 is abundant (9690 is more than 8742). Euler's totient φ(8742) = 2760 numbers up to 8742 share no factor with it.
- 4
The digits of 8742 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 109 steps to reach 1.
LaTeX source of the formulas on this page
\[ 8742 = 2 \times 3 \times 31 \times 47 \]
8742 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 18432 |
| Euler totient φ(n) | 2760 |
| Square | 76422564 |
| Cube | 668086054488 |
| Square root | 93.498663 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 109 |
| Scientific notation | 8.742 × |
8742 in other forms
| Form | Value |
|---|---|
| In words | eight thousand seven hundred and forty-two |
| Binary (base 2) | 10001000100110 |
| Octal (base 8) | 21046 |
| Hexadecimal (base 16) | 2226 |
| Base 3 | 102222210 |
| As time | 8742 seconds = 2 h 25 min 42 s |
Is 8742 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (8742 ÷ 2 = 4371) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (8742 ÷ 3 = 2914) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (8742 ÷ 6 = 1457) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 | No (remainder 6) | 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 2) | 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 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 8742 a prime number?
No. 8742 = 2 × 3 × 31 × 47, so it is divisible by 2.
What are the factors of 8742?
1, 2, 3, 6, 31, 47, 62, 93, 94, 141, 186, 282, 1457, 2914, 4371, 8742.
What is 8742 in binary?
10001000100110 (hexadecimal 2226, octal 21046).
What is the square root of 8742?
About 93.4987.
Is 8742 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 8742?
8742 is a happy number: repeatedly adding the squares of its digits reaches 1.