The number 28990
28990 is a composite number with 16 divisors. Its prime factorisation is 2 × 5 × 13 × 223. Divisors (16): 1, 2, 5, 10, 13, 26, 65, 130, 223, 446, 1115, 2230, 2899, 5798, 14495, 28990.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28990: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
28990 is composite. Its prime factorisation is
- 3
The divisors add up to 56448; without 28990 itself that is 27458, so 28990 is deficient (27458 is less than 28990). Euler's totient φ(28990) = 10656 numbers up to 28990 share no factor with it.
- 4
The digits of 28990 add up to 28, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 183 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28990 = 2 \times 5 \times 13 \times 223 \]
28990 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 56448 |
| Euler totient φ(n) | 10656 |
| Square | 840420100 |
| Cube | 24363778699000 |
| Square root | 170.264500 |
| Digit sum / digital root | 28 / 1 |
| Collatz steps to 1 | 183 |
| Scientific notation | 2.899 × |
28990 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand nine hundred and ninety |
| Binary (base 2) | 111000100111110 |
| Octal (base 8) | 70476 |
| Hexadecimal (base 16) | 713E |
| Base 3 | 1110202201 |
| As time | 28990 seconds = 8 h 3 min 10 s |
Is 28990 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (28990 ÷ 2 = 14495) | 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 | Yes (28990 ÷ 5 = 5798) | 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 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 6) | 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 | Yes (28990 ÷ 10 = 2899) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | 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 28990 a prime number?
No. 28990 = 2 × 5 × 13 × 223, so it is divisible by 2.
What are the factors of 28990?
1, 2, 5, 10, 13, 26, 65, 130, 223, 446, 1115, 2230, 2899, 5798, 14495, 28990.
What is 28990 in binary?
111000100111110 (hexadecimal 713E, octal 70476).
What is the square root of 28990?
About 170.2645.
Is 28990 divisible by 3?
No. Its digits add up to 28, which is not a multiple of 3.
What is special about the number 28990?
28990 is a happy number: repeatedly adding the squares of its digits reaches 1.