The number 21177
21177 is a composite number with 12 divisors. Its prime factorisation is × 13 × 181. Divisors (12): 1, 3, 9, 13, 39, 117, 181, 543, 1629, 2353, 7059, 21177.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21177 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21177 is composite. Its prime factorisation is
- 3
The divisors add up to 33124; without 21177 itself that is 11947, so 21177 is deficient (11947 is less than 21177). Euler's totient φ(21177) = 12960 numbers up to 21177 share no factor with it.
- 4
The digits of 21177 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 149 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21177 = 3^{2} \times 13 \times 181 \]21177 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 33124 |
| Euler totient φ(n) | 12960 |
| Square | 448465329 |
| Cube | 9497150272233 |
| Square root | 145.523194 (= 3√2353) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 149 |
| Scientific notation | 2.1177 × |
21177 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and seventy-seven |
| Binary (base 2) | 101001010111001 |
| Octal (base 8) | 51271 |
| Hexadecimal (base 16) | 52B9 |
| Base 3 | 1002001100 |
| As time | 21177 seconds = 5 h 52 min 57 s |
Is 21177 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 | Yes (21177 ÷ 3 = 7059) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 | Yes (21177 ÷ 9 = 2353) | 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 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21177 a prime number?
No. 21177 = × 13 × 181, so it is divisible by 3.
What are the factors of 21177?
1, 3, 9, 13, 39, 117, 181, 543, 1629, 2353, 7059, 21177.
What is 21177 in binary?
101001010111001 (hexadecimal 52B9, octal 51271).
What is the square root of 21177?
About 145.5232, exactly 3√2353.
Is 21177 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 21177?
It is a composite number with 12 divisors.