The number 21148
21148 is a composite number with 12 divisors. Its prime factorisation is × 17 × 311. Divisors (12): 1, 2, 4, 17, 34, 68, 311, 622, 1244, 5287, 10574, 21148.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21148: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
21148 is composite. Its prime factorisation is
- 3
The divisors add up to 39312; without 21148 itself that is 18164, so 21148 is deficient (18164 is less than 21148). Euler's totient φ(21148) = 9920 numbers up to 21148 share no factor with it.
- 4
The digits of 21148 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 79 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21148 = 2^{2} \times 17 \times 311 \]21148 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 39312 |
| Euler totient φ(n) | 9920 |
| Square | 447237904 |
| Cube | 9458187193792 |
| Square root | 145.423519 (= 2√5287) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 79 |
| Scientific notation | 2.1148 × |
21148 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and forty-eight |
| Binary (base 2) | 101001010011100 |
| Octal (base 8) | 51234 |
| Hexadecimal (base 16) | 529C |
| Base 3 | 1002000021 |
| As time | 21148 seconds = 5 h 52 min 28 s |
Is 21148 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21148 ÷ 2 = 10574) | 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 | Yes (21148 ÷ 4 = 5287) | 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 1) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | 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 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21148 a prime number?
No. 21148 = × 17 × 311, so it is divisible by 2.
What are the factors of 21148?
1, 2, 4, 17, 34, 68, 311, 622, 1244, 5287, 10574, 21148.
What is 21148 in binary?
101001010011100 (hexadecimal 529C, octal 51234).
What is the square root of 21148?
About 145.4235, exactly 2√5287.
Is 21148 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 21148?
21148 is a happy number: repeatedly adding the squares of its digits reaches 1.