The number 28018
28018 is a composite number with 4 divisors. Its prime factorisation is 2 × 14009. Divisors (4): 1, 2, 14009, 28018.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28018: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 2 × 14009, the product of two primes.
- 2
28018 is composite. Its prime factorisation is
- 3
The divisors add up to 42030; without 28018 itself that is 14012, so 28018 is deficient (14012 is less than 28018). Euler's totient φ(28018) = 14008 numbers up to 28018 share no factor with it.
- 4
The digits of 28018 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 152 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28018 = 2 \times 14009 \]
28018 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 42030 |
| Euler totient φ(n) | 14008 |
| Square | 785008324 |
| Cube | 21994363221832 |
| Square root | 167.385782 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 152 |
| Scientific notation | 2.8018 × |
28018 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand and eighteen |
| Binary (base 2) | 110110101110010 |
| Octal (base 8) | 66562 |
| Hexadecimal (base 16) | 6D72 |
| Base 3 | 1102102201 |
| As time | 28018 seconds = 7 h 46 min 58 s |
Is 28018 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (28018 ÷ 2 = 14009) | 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 | No (remainder 2) | 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 | No (remainder 2) | 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 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28018 a prime number?
No. 28018 = 2 × 14009, so it is divisible by 2.
What are the factors of 28018?
1, 2, 14009, 28018.
What is 28018 in binary?
110110101110010 (hexadecimal 6D72, octal 66562).
What is the square root of 28018?
About 167.3858.
Is 28018 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 28018?
28018 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 2 × 14009, the product of two primes.