The number 28801
28801 is a composite number with 4 divisors. Its prime factorisation is 83 × 347. Divisors (4): 1, 83, 347, 28801.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28801: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 83 × 347, the product of two primes.
- 2
28801 is composite. Its prime factorisation is
- 3
The divisors add up to 29232; without 28801 itself that is 431, so 28801 is deficient (431 is less than 28801). Euler's totient φ(28801) = 28372 numbers up to 28801 share no factor with it.
- 4
The digits of 28801 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 72 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28801 = 83 \times 347 \]
28801 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 29232 |
| Euler totient φ(n) | 28372 |
| Square | 829497601 |
| Cube | 23890360406401 |
| Square root | 169.708574 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 72 |
| Scientific notation | 2.8801 × |
28801 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand eight hundred and one |
| Binary (base 2) | 111000010000001 |
| Octal (base 8) | 70201 |
| Hexadecimal (base 16) | 7081 |
| Base 3 | 1110111201 |
| As time | 28801 seconds = 8 h 0 min 1 s |
Is 28801 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 1) | 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 3) | 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 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | 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 28801 a prime number?
No. 28801 = 83 × 347, so it is divisible by 83.
What are the factors of 28801?
1, 83, 347, 28801.
What is 28801 in binary?
111000010000001 (hexadecimal 7081, octal 70201).
What is the square root of 28801?
About 169.7086.
Is 28801 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 28801?
28801 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 83 × 347, the product of two primes.