The number 21477
21477 is a binary palindrome (101001111100101). Its prime factorisation is 3 × 7159. Divisors (4): 1, 3, 7159, 21477.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21477: a binary palindrome (101001111100101); a semiprime: 3 × 7159, the product of two primes.
- 2
21477 is composite. Its prime factorisation is
- 3
The divisors add up to 28640; without 21477 itself that is 7163, so 21477 is deficient (7163 is less than 21477). Euler's totient φ(21477) = 14316 numbers up to 21477 share no factor with it.
- 4
The digits of 21477 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 74 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21477 = 3 \times 7159 \]
21477 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 28640 |
| Euler totient φ(n) | 14316 |
| Square | 461261529 |
| Cube | 9906513858333 |
| Square root | 146.550333 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 74 |
| Scientific notation | 2.1477 × |
21477 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and seventy-seven |
| Binary (base 2) | 101001111100101 |
| Octal (base 8) | 51745 |
| Hexadecimal (base 16) | 53E5 |
| Base 3 | 1002110110 |
| As time | 21477 seconds = 5 h 57 min 57 s |
Is 21477 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 (21477 ÷ 3 = 7159) | 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 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 3) | 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 5) | 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 21477 a prime number?
No. 21477 = 3 × 7159, so it is divisible by 3.
What are the factors of 21477?
1, 3, 7159, 21477.
What is 21477 in binary?
101001111100101 (hexadecimal 53E5, octal 51745).
What is the square root of 21477?
About 146.5503.
Is 21477 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 21477?
21477 is a binary palindrome (101001111100101); a semiprime: 3 × 7159, the product of two primes.