The number 15521
15521 is a composite number with 8 divisors. Its prime factorisation is 11 × 17 × 83. Divisors (8): 1, 11, 17, 83, 187, 913, 1411, 15521.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
15521 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
15521 is composite. Its prime factorisation is
- 3
The divisors add up to 18144; without 15521 itself that is 2623, so 15521 is deficient (2623 is less than 15521). Euler's totient φ(15521) = 13120 numbers up to 15521 share no factor with it.
- 4
The digits of 15521 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 133 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15521 = 11 \times 17 \times 83 \]
15521 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 18144 |
| Euler totient φ(n) | 13120 |
| Square | 240901441 |
| Cube | 3739031265761 |
| Square root | 124.583305 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 133 |
| Scientific notation | 1.5521 × |
15521 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand five hundred and twenty-one |
| Binary (base 2) | 11110010100001 |
| Octal (base 8) | 36241 |
| Hexadecimal (base 16) | 3CA1 |
| Base 3 | 210021212 |
| As time | 15521 seconds = 4 h 18 min 41 s |
Is 15521 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 1) | 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 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 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (15521 ÷ 11 = 1411) | 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 15521 a prime number?
No. 15521 = 11 × 17 × 83, so it is divisible by 11.
What are the factors of 15521?
1, 11, 17, 83, 187, 913, 1411, 15521.
What is 15521 in binary?
11110010100001 (hexadecimal 3CA1, octal 36241).
What is the square root of 15521?
About 124.5833.
Is 15521 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 15521?
It is a composite number with 8 divisors.