The number 21535
21535 is a composite number with 8 divisors. Its prime factorisation is 5 × 59 × 73. Divisors (8): 1, 5, 59, 73, 295, 365, 4307, 21535.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21535 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21535 is composite. Its prime factorisation is
- 3
The divisors add up to 26640; without 21535 itself that is 5105, so 21535 is deficient (5105 is less than 21535). Euler's totient φ(21535) = 16704 numbers up to 21535 share no factor with it.
- 4
The digits of 21535 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 100 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21535 = 5 \times 59 \times 73 \]
21535 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 26640 |
| Euler totient φ(n) | 16704 |
| Square | 463756225 |
| Cube | 9986990305375 |
| Square root | 146.748083 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 100 |
| Scientific notation | 2.1535 × |
21535 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand five hundred and thirty-five |
| Binary (base 2) | 101010000011111 |
| Octal (base 8) | 52037 |
| Hexadecimal (base 16) | 541F |
| Base 3 | 1002112121 |
| As time | 21535 seconds = 5 h 58 min 55 s |
Is 21535 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 1) | 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 | Yes (21535 ÷ 5 = 4307) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21535 a prime number?
No. 21535 = 5 × 59 × 73, so it is divisible by 5.
What are the factors of 21535?
1, 5, 59, 73, 295, 365, 4307, 21535.
What is 21535 in binary?
101010000011111 (hexadecimal 541F, octal 52037).
What is the square root of 21535?
About 146.7481.
Is 21535 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 21535?
It is a composite number with 8 divisors.