The number 3998
3998 is a composite number with 4 divisors. Its prime factorisation is 2 × 1999. Divisors (4): 1, 2, 1999, 3998.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 3998: a semiprime: 2 × 1999, the product of two primes.
- 2
3998 is composite. Its prime factorisation is
- 3
The divisors add up to 6000; without 3998 itself that is 2002, so 3998 is deficient (2002 is less than 3998). Euler's totient φ(3998) = 1998 numbers up to 3998 share no factor with it.
- 4
The digits of 3998 add up to 29, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 51 steps to reach 1.
LaTeX source of the formulas on this page
\[ 3998 = 2 \times 1999 \]
3998 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 6000 |
| Euler totient φ(n) | 1998 |
| Square | 15984004 |
| Cube | 63904047992 |
| Square root | 63.229740 |
| Digit sum / digital root | 29 / 2 |
| Collatz steps to 1 | 51 |
| Scientific notation | 3.998 × |
3998 in other forms
| Form | Value |
|---|---|
| In words | three thousand nine hundred and ninety-eight |
| Roman numerals | MMMCMXCVIII |
| Binary (base 2) | 111110011110 |
| Octal (base 8) | 7636 |
| Hexadecimal (base 16) | F9E |
| Base 3 | 12111002 |
| As time | 3998 seconds = 1 h 6 min 38 s |
Is 3998 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (3998 ÷ 2 = 1999) | 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 1) | 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 2) | 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 5) | 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 3998 a prime number?
No. 3998 = 2 × 1999, so it is divisible by 2.
What are the factors of 3998?
1, 2, 1999, 3998.
What is 3998 in binary?
111110011110 (hexadecimal F9E, octal 7636).
What is the square root of 3998?
About 63.2297.
What is 3998 in Roman numerals?
MMMCMXCVIII.
Is 3998 divisible by 3?
No. Its digits add up to 29, which is not a multiple of 3.
What is special about the number 3998?
3998 is a semiprime: 2 × 1999, the product of two primes.