The number 18101
18101 is a composite number with 4 divisors. Its prime factorisation is 23 × 787. Divisors (4): 1, 23, 787, 18101.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18101: a semiprime: 23 × 787, the product of two primes.
- 2
18101 is composite. Its prime factorisation is
- 3
The divisors add up to 18912; without 18101 itself that is 811, so 18101 is deficient (811 is less than 18101). Euler's totient φ(18101) = 17292 numbers up to 18101 share no factor with it.
- 4
The digits of 18101 add up to 11, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 40 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18101 = 23 \times 787 \]
18101 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 18912 |
| Euler totient φ(n) | 17292 |
| Square | 327646201 |
| Cube | 5930723884301 |
| Square root | 134.539957 |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 40 |
| Scientific notation | 1.8101 × |
18101 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand one hundred and one |
| Binary (base 2) | 100011010110101 |
| Octal (base 8) | 43265 |
| Hexadecimal (base 16) | 46B5 |
| Base 3 | 220211102 |
| As time | 18101 seconds = 5 h 1 min 41 s |
Is 18101 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 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | 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 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 5) | 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 1) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18101 a prime number?
No. 18101 = 23 × 787, so it is divisible by 23.
What are the factors of 18101?
1, 23, 787, 18101.
What is 18101 in binary?
100011010110101 (hexadecimal 46B5, octal 43265).
What is the square root of 18101?
About 134.5400.
Is 18101 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 18101?
18101 is a semiprime: 23 × 787, the product of two primes.