The number 15321
15321 is a composite number with 4 divisors. Its prime factorisation is 3 × 5107. Divisors (4): 1, 3, 5107, 15321.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 15321: a semiprime: 3 × 5107, the product of two primes.
- 2
15321 is composite. Its prime factorisation is
- 3
The divisors add up to 20432; without 15321 itself that is 5111, so 15321 is deficient (5111 is less than 15321). Euler's totient φ(15321) = 10212 numbers up to 15321 share no factor with it.
- 4
The digits of 15321 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 40 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15321 = 3 \times 5107 \]
15321 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 20432 |
| Euler totient φ(n) | 10212 |
| Square | 234733041 |
| Cube | 3596344921161 |
| Square root | 123.778027 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 40 |
| Scientific notation | 1.5321 × |
15321 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand three hundred and twenty-one |
| Binary (base 2) | 11101111011001 |
| Octal (base 8) | 35731 |
| Hexadecimal (base 16) | 3BD9 |
| Base 3 | 210000110 |
| As time | 15321 seconds = 4 h 15 min 21 s |
Is 15321 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 (15321 ÷ 3 = 5107) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 3) | 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 | No (remainder 9) | 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 15321 a prime number?
No. 15321 = 3 × 5107, so it is divisible by 3.
What are the factors of 15321?
1, 3, 5107, 15321.
What is 15321 in binary?
11101111011001 (hexadecimal 3BD9, octal 35731).
What is the square root of 15321?
About 123.7780.
Is 15321 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 15321?
15321 is a semiprime: 3 × 5107, the product of two primes.