The number 28013
28013 is a composite number with 4 divisors. Its prime factorisation is 109 × 257. Divisors (4): 1, 109, 257, 28013.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28013: a semiprime: 109 × 257, the product of two primes.
- 2
28013 is composite. Its prime factorisation is
- 3
The divisors add up to 28380; without 28013 itself that is 367, so 28013 is deficient (367 is less than 28013). Euler's totient φ(28013) = 27648 numbers up to 28013 share no factor with it.
- 4
The digits of 28013 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 152 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28013 = 109 \times 257 \]
28013 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 28380 |
| Euler totient φ(n) | 27648 |
| Square | 784728169 |
| Cube | 21982590198197 |
| Square root | 167.370846 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 152 |
| Scientific notation | 2.8013 × |
28013 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand and thirteen |
| Binary (base 2) | 110110101101101 |
| Octal (base 8) | 66555 |
| Hexadecimal (base 16) | 6D6D |
| Base 3 | 1102102112 |
| As time | 28013 seconds = 7 h 46 min 53 s |
Is 28013 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | 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 5) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28013 a prime number?
No. 28013 = 109 × 257, so it is divisible by 109.
What are the factors of 28013?
1, 109, 257, 28013.
What is 28013 in binary?
110110101101101 (hexadecimal 6D6D, octal 66555).
What is the square root of 28013?
About 167.3708.
Is 28013 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 28013?
28013 is a semiprime: 109 × 257, the product of two primes.