The number 39990
39990 is a composite number with 32 divisors. Its prime factorisation is 2 × 3 × 5 × 31 × 43. Divisors (32): 1, 2, 3, 5, 6, 10, 15, 30, 31, 43, 62, 86, 93, 129, 155, 186 … 39990.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 39990: a Harshad number: divisible by its digit sum 30.
- 2
39990 is composite. Its prime factorisation is
- 3
The divisors add up to 101376; without 39990 itself that is 61386, so 39990 is abundant (61386 is more than 39990). Euler's totient φ(39990) = 10080 numbers up to 39990 share no factor with it.
- 4
The digits of 39990 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 67 steps to reach 1.
LaTeX source of the formulas on this page
\[ 39990 = 2 \times 3 \times 5 \times 31 \times 43 \]
39990 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 101376 |
| Euler totient φ(n) | 10080 |
| Square | 1599200100 |
| Cube | 63952011999000 |
| Square root | 199.974998 |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 67 |
| Scientific notation | 3.999 × |
39990 in other forms
| Form | Value |
|---|---|
| In words | thirty-nine thousand nine hundred and ninety |
| Binary (base 2) | 1001110000110110 |
| Octal (base 8) | 116066 |
| Hexadecimal (base 16) | 9C36 |
| Base 3 | 2000212010 |
| As time | 39990 seconds = 11 h 6 min 30 s |
Is 39990 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (39990 ÷ 2 = 19995) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (39990 ÷ 3 = 13330) | 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 (39990 ÷ 5 = 7998) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (39990 ÷ 6 = 6665) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 | Yes (39990 ÷ 10 = 3999) | 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 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 39990 a prime number?
No. 39990 = 2 × 3 × 5 × 31 × 43, so it is divisible by 2.
What are the factors of 39990?
1, 2, 3, 5, 6, 10, 15, 30, 31, 43, 62, 86, 93, 129, 155, 186, 215, 258, 310, 430, 465, 645, 930, 1290, 1333, 2666, 3999, 6665, 7998, 13330, 19995, 39990.
What is 39990 in binary?
1001110000110110 (hexadecimal 9C36, octal 116066).
What is the square root of 39990?
About 199.9750.
Is 39990 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 39990?
39990 is a Harshad number: divisible by its digit sum 30.