The number 20015
20015 is a composite number with 4 divisors. Its prime factorisation is 5 × 4003. Divisors (4): 1, 5, 4003, 20015.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20015: a semiprime: 5 × 4003, the product of two primes.
- 2
20015 is composite. Its prime factorisation is
- 3
The divisors add up to 24024; without 20015 itself that is 4009, so 20015 is deficient (4009 is less than 20015). Euler's totient φ(20015) = 16008 numbers up to 20015 share no factor with it.
- 4
The digits of 20015 add up to 8, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 66 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20015 = 5 \times 4003 \]
20015 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 24024 |
| Euler totient φ(n) | 16008 |
| Square | 400600225 |
| Cube | 8018013503375 |
| Square root | 141.474379 |
| Digit sum / digital root | 8 / 8 |
| Collatz steps to 1 | 66 |
| Scientific notation | 2.0015 × |
20015 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand and fifteen |
| Binary (base 2) | 100111000101111 |
| Octal (base 8) | 47057 |
| Hexadecimal (base 16) | 4E2F |
| Base 3 | 1000110022 |
| As time | 20015 seconds = 5 h 33 min 35 s |
Is 20015 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (20015 ÷ 5 = 4003) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20015 a prime number?
No. 20015 = 5 × 4003, so it is divisible by 5.
What are the factors of 20015?
1, 5, 4003, 20015.
What is 20015 in binary?
100111000101111 (hexadecimal 4E2F, octal 47057).
What is the square root of 20015?
About 141.4744.
Is 20015 divisible by 3?
No. Its digits add up to 8, which is not a multiple of 3.
What is special about the number 20015?
20015 is a semiprime: 5 × 4003, the product of two primes.