The number 21197
21197 is a composite number with 8 divisors. Its prime factorisation is 11 × 41 × 47. Divisors (8): 1, 11, 41, 47, 451, 517, 1927, 21197.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21197 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21197 is composite. Its prime factorisation is
- 3
The divisors add up to 24192; without 21197 itself that is 2995, so 21197 is deficient (2995 is less than 21197). Euler's totient φ(21197) = 18400 numbers up to 21197 share no factor with it.
- 4
The digits of 21197 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 100 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21197 = 11 \times 41 \times 47 \]
21197 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 24192 |
| Euler totient φ(n) | 18400 |
| Square | 449312809 |
| Cube | 9524083612373 |
| Square root | 145.591895 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 100 |
| Scientific notation | 2.1197 × |
21197 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and ninety-seven |
| Binary (base 2) | 101001011001101 |
| Octal (base 8) | 51315 |
| Hexadecimal (base 16) | 52CD |
| Base 3 | 1002002002 |
| As time | 21197 seconds = 5 h 53 min 17 s |
Is 21197 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 2) | 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 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (21197 ÷ 11 = 1927) | 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 21197 a prime number?
No. 21197 = 11 × 41 × 47, so it is divisible by 11.
What are the factors of 21197?
1, 11, 41, 47, 451, 517, 1927, 21197.
What is 21197 in binary?
101001011001101 (hexadecimal 52CD, octal 51315).
What is the square root of 21197?
About 145.5919.
Is 21197 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 21197?
It is a composite number with 8 divisors.