The number 28993
28993 is a composite number with 4 divisors. Its prime factorisation is 79 × 367. Divisors (4): 1, 79, 367, 28993.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28993: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 79 × 367, the product of two primes.
- 2
28993 is composite. Its prime factorisation is
- 3
The divisors add up to 29440; without 28993 itself that is 447, so 28993 is deficient (447 is less than 28993). Euler's totient φ(28993) = 28548 numbers up to 28993 share no factor with it.
- 4
The digits of 28993 add up to 31, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 72 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28993 = 79 \times 367 \]
28993 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 29440 |
| Euler totient φ(n) | 28548 |
| Square | 840594049 |
| Cube | 24371343262657 |
| Square root | 170.273310 |
| Digit sum / digital root | 31 / 4 |
| Collatz steps to 1 | 72 |
| Scientific notation | 2.8993 × |
28993 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand nine hundred and ninety-three |
| Binary (base 2) | 111000101000001 |
| Octal (base 8) | 70501 |
| Hexadecimal (base 16) | 7141 |
| Base 3 | 1110202211 |
| As time | 28993 seconds = 8 h 3 min 13 s |
Is 28993 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 1) | 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 1) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28993 a prime number?
No. 28993 = 79 × 367, so it is divisible by 79.
What are the factors of 28993?
1, 79, 367, 28993.
What is 28993 in binary?
111000101000001 (hexadecimal 7141, octal 70501).
What is the square root of 28993?
About 170.2733.
Is 28993 divisible by 3?
No. Its digits add up to 31, which is not a multiple of 3.
What is special about the number 28993?
28993 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 79 × 367, the product of two primes.