The number 31990
31990 is a composite number with 16 divisors. Its prime factorisation is 2 × 5 × 7 × 457. Divisors (16): 1, 2, 5, 7, 10, 14, 35, 70, 457, 914, 2285, 3199, 4570, 6398, 15995, 31990.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31990 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31990 is composite. Its prime factorisation is
- 3
The divisors add up to 65952; without 31990 itself that is 33962, so 31990 is abundant (33962 is more than 31990). Euler's totient φ(31990) = 10944 numbers up to 31990 share no factor with it.
- 4
The digits of 31990 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 54 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31990 = 2 \times 5 \times 7 \times 457 \]
31990 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 65952 |
| Euler totient φ(n) | 10944 |
| Square | 1023360100 |
| Cube | 32737289599000 |
| Square root | 178.857485 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 54 |
| Scientific notation | 3.199 × |
31990 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred and ninety |
| Binary (base 2) | 111110011110110 |
| Octal (base 8) | 76366 |
| Hexadecimal (base 16) | 7CF6 |
| Base 3 | 1121212211 |
| As time | 31990 seconds = 8 h 53 min 10 s |
Is 31990 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31990 ÷ 2 = 15995) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (31990 ÷ 5 = 6398) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (31990 ÷ 7 = 4570) | 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 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (31990 ÷ 10 = 3199) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31990 a prime number?
No. 31990 = 2 × 5 × 7 × 457, so it is divisible by 2.
What are the factors of 31990?
1, 2, 5, 7, 10, 14, 35, 70, 457, 914, 2285, 3199, 4570, 6398, 15995, 31990.
What is 31990 in binary?
111110011110110 (hexadecimal 7CF6, octal 76366).
What is the square root of 31990?
About 178.8575.
Is 31990 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 31990?
It is a composite number with 16 divisors.