The number 15998
15998 is a composite number with 8 divisors. Its prime factorisation is 2 × 19 × 421. Divisors (8): 1, 2, 19, 38, 421, 842, 7999, 15998.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
15998 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
15998 is composite. Its prime factorisation is
- 3
The divisors add up to 25320; without 15998 itself that is 9322, so 15998 is deficient (9322 is less than 15998). Euler's totient φ(15998) = 7560 numbers up to 15998 share no factor with it.
- 4
The digits of 15998 add up to 32, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 190 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15998 = 2 \times 19 \times 421 \]
15998 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 25320 |
| Euler totient φ(n) | 7560 |
| Square | 255936004 |
| Cube | 4094464191992 |
| Square root | 126.483200 |
| Digit sum / digital root | 32 / 5 |
| Collatz steps to 1 | 190 |
| Scientific notation | 1.5998 × |
15998 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand nine hundred and ninety-eight |
| Binary (base 2) | 11111001111110 |
| Octal (base 8) | 37176 |
| Hexadecimal (base 16) | 3E7E |
| Base 3 | 210221112 |
| As time | 15998 seconds = 4 h 26 min 38 s |
Is 15998 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (15998 ÷ 2 = 7999) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 6) | 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 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 15998 a prime number?
No. 15998 = 2 × 19 × 421, so it is divisible by 2.
What are the factors of 15998?
1, 2, 19, 38, 421, 842, 7999, 15998.
What is 15998 in binary?
11111001111110 (hexadecimal 3E7E, octal 37176).
What is the square root of 15998?
About 126.4832.
Is 15998 divisible by 3?
No. Its digits add up to 32, which is not a multiple of 3.
What is special about the number 15998?
It is a composite number with 8 divisors.