The number 2101
2101 is a composite number with 4 divisors. Its prime factorisation is 11 × 191. Divisors (4): 1, 11, 191, 2101.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 2101: a semiprime: 11 × 191, the product of two primes.
- 2
2101 is composite. Its prime factorisation is
- 3
The divisors add up to 2304; without 2101 itself that is 203, so 2101 is deficient (203 is less than 2101). Euler's totient φ(2101) = 1900 numbers up to 2101 share no factor with it.
- 4
The digits of 2101 add up to 4, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 32 steps to reach 1.
LaTeX source of the formulas on this page
\[ 2101 = 11 \times 191 \]
2101 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 2304 |
| Euler totient φ(n) | 1900 |
| Square | 4414201 |
| Cube | 9274236301 |
| Square root | 45.836667 |
| Digit sum / digital root | 4 / 4 |
| Collatz steps to 1 | 32 |
| Scientific notation | 2.101 × |
2101 in other forms
| Form | Value |
|---|---|
| In words | two thousand one hundred and one |
| Roman numerals | MMCI |
| Binary (base 2) | 100000110101 |
| Octal (base 8) | 4065 |
| Hexadecimal (base 16) | 835 |
| Base 3 | 2212211 |
| As time | 2101 seconds = 35 min 1 s |
Is 2101 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 1) | 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 1) | 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 5) | 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 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (2101 ÷ 11 = 191) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 2101 a prime number?
No. 2101 = 11 × 191, so it is divisible by 11.
What are the factors of 2101?
1, 11, 191, 2101.
What is 2101 in binary?
100000110101 (hexadecimal 835, octal 4065).
What is the square root of 2101?
About 45.8367.
What is 2101 in Roman numerals?
MMCI.
Is 2101 divisible by 3?
No. Its digits add up to 4, which is not a multiple of 3.
What is special about the number 2101?
2101 is a semiprime: 11 × 191, the product of two primes.