The number 78042
78042 is a composite number with 8 divisors. Its prime factorisation is 2 × 3 × 13007. Divisors (8): 1, 2, 3, 6, 13007, 26014, 39021, 78042.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 78042: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
78042 is composite. Its prime factorisation is
- 3
The divisors add up to 156096; without 78042 itself that is 78054, so 78042 is abundant (78054 is more than 78042). Euler's totient φ(78042) = 26012 numbers up to 78042 share no factor with it.
- 4
The digits of 78042 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 63 steps to reach 1.
LaTeX source of the formulas on this page
\[ 78042 = 2 \times 3 \times 13007 \]
78042 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 156096 |
| Euler totient φ(n) | 26012 |
| Square | 6090553764 |
| Cube | 475318996850088 |
| Square root | 279.359983 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 63 |
| Scientific notation | 7.8042 × |
78042 in other forms
| Form | Value |
|---|---|
| In words | seventy-eight thousand and forty-two |
| Binary (base 2) | 10011000011011010 |
| Octal (base 8) | 230332 |
| Hexadecimal (base 16) | 130DA |
| Base 3 | 10222001110 |
| As time | 78042 seconds = 21 h 40 min 42 s |
Is 78042 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (78042 ÷ 2 = 39021) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (78042 ÷ 3 = 26014) | 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 (78042 ÷ 6 = 13007) | 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 2) | 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 78042 a prime number?
No. 78042 = 2 × 3 × 13007, so it is divisible by 2.
What are the factors of 78042?
1, 2, 3, 6, 13007, 26014, 39021, 78042.
What is 78042 in binary?
10011000011011010 (hexadecimal 130DA, octal 230332).
What is the square root of 78042?
About 279.3600.
Is 78042 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 78042?
78042 is a happy number: repeatedly adding the squares of its digits reaches 1.