The number 21167
21167 is a composite number with 4 divisors. Its prime factorisation is 61 × 347. Divisors (4): 1, 61, 347, 21167.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21167: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 61 × 347, the product of two primes.
- 2
21167 is composite. Its prime factorisation is
- 3
The divisors add up to 21576; without 21167 itself that is 409, so 21167 is deficient (409 is less than 21167). Euler's totient φ(21167) = 20760 numbers up to 21167 share no factor with it.
- 4
The digits of 21167 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 105 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21167 = 61 \times 347 \]
21167 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 21576 |
| Euler totient φ(n) | 20760 |
| Square | 448041889 |
| Cube | 9483702664463 |
| Square root | 145.488831 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 105 |
| Scientific notation | 2.1167 × |
21167 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and sixty-seven |
| Binary (base 2) | 101001010101111 |
| Octal (base 8) | 51257 |
| Hexadecimal (base 16) | 52AF |
| Base 3 | 1002000222 |
| As time | 21167 seconds = 5 h 52 min 47 s |
Is 21167 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 3) | 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 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | 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 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21167 a prime number?
No. 21167 = 61 × 347, so it is divisible by 61.
What are the factors of 21167?
1, 61, 347, 21167.
What is 21167 in binary?
101001010101111 (hexadecimal 52AF, octal 51257).
What is the square root of 21167?
About 145.4888.
Is 21167 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21167?
21167 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 61 × 347, the product of two primes.