The number 15997
15997 is a composite number with 4 divisors. Its prime factorisation is 17 × 941. Divisors (4): 1, 17, 941, 15997.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 15997: a semiprime: 17 × 941, the product of two primes.
- 2
15997 is composite. Its prime factorisation is
- 3
The divisors add up to 16956; without 15997 itself that is 959, so 15997 is deficient (959 is less than 15997). Euler's totient φ(15997) = 15040 numbers up to 15997 share no factor with it.
- 4
The digits of 15997 add up to 31, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 190 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15997 = 17 \times 941 \]
15997 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 16956 |
| Euler totient φ(n) | 15040 |
| Square | 255904009 |
| Cube | 4093696431973 |
| Square root | 126.479247 |
| Digit sum / digital root | 31 / 4 |
| Collatz steps to 1 | 190 |
| Scientific notation | 1.5997 × |
15997 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand nine hundred and ninety-seven |
| Binary (base 2) | 11111001111101 |
| Octal (base 8) | 37175 |
| Hexadecimal (base 16) | 3E7D |
| Base 3 | 210221111 |
| As time | 15997 seconds = 4 h 26 min 37 s |
Is 15997 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 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 1) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 15997 a prime number?
No. 15997 = 17 × 941, so it is divisible by 17.
What are the factors of 15997?
1, 17, 941, 15997.
What is 15997 in binary?
11111001111101 (hexadecimal 3E7D, octal 37175).
What is the square root of 15997?
About 126.4792.
Is 15997 divisible by 3?
No. Its digits add up to 31, which is not a multiple of 3.
What is special about the number 15997?
15997 is a semiprime: 17 × 941, the product of two primes.