The number 31998
31998 is a composite number with 8 divisors. Its prime factorisation is 2 × 3 × 5333. Divisors (8): 1, 2, 3, 6, 5333, 10666, 15999, 31998.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31998: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
31998 is composite. Its prime factorisation is
- 3
The divisors add up to 64008; without 31998 itself that is 32010, so 31998 is abundant (32010 is more than 31998). Euler's totient φ(31998) = 10664 numbers up to 31998 share no factor with it.
- 4
The digits of 31998 add up to 30, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 98 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31998 = 2 \times 3 \times 5333 \]
31998 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 64008 |
| Euler totient φ(n) | 10664 |
| Square | 1023872004 |
| Cube | 32761856383992 |
| Square root | 178.879848 |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 98 |
| Scientific notation | 3.1998 × |
31998 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred and ninety-eight |
| Binary (base 2) | 111110011111110 |
| Octal (base 8) | 76376 |
| Hexadecimal (base 16) | 7CFE |
| Base 3 | 1121220010 |
| As time | 31998 seconds = 8 h 53 min 18 s |
Is 31998 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31998 ÷ 2 = 15999) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (31998 ÷ 3 = 10666) | 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 | Yes (31998 ÷ 6 = 5333) | 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 3) | 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 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31998 a prime number?
No. 31998 = 2 × 3 × 5333, so it is divisible by 2.
What are the factors of 31998?
1, 2, 3, 6, 5333, 10666, 15999, 31998.
What is 31998 in binary?
111110011111110 (hexadecimal 7CFE, octal 76376).
What is the square root of 31998?
About 178.8798.
Is 31998 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 31998?
31998 is a happy number: repeatedly adding the squares of its digits reaches 1.