The number 2109
2109 is a composite number with 8 divisors. Its prime factorisation is 3 × 19 × 37. Divisors (8): 1, 3, 19, 37, 57, 111, 703, 2109.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 2109: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
2109 is composite. Its prime factorisation is
- 3
The divisors add up to 3040; without 2109 itself that is 931, so 2109 is deficient (931 is less than 2109). Euler's totient φ(2109) = 1296 numbers up to 2109 share no factor with it.
- 4
The digits of 2109 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 81 steps to reach 1.
LaTeX source of the formulas on this page
\[ 2109 = 3 \times 19 \times 37 \]
2109 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 3040 |
| Euler totient φ(n) | 1296 |
| Square | 4447881 |
| Cube | 9380581029 |
| Square root | 45.923850 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 81 |
| Scientific notation | 2.109 × |
2109 in other forms
| Form | Value |
|---|---|
| In words | two thousand one hundred and nine |
| Roman numerals | MMCIX |
| Binary (base 2) | 100000111101 |
| Octal (base 8) | 4075 |
| Hexadecimal (base 16) | 83D |
| Base 3 | 2220010 |
| As time | 2109 seconds = 35 min 9 s |
Is 2109 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 | Yes (2109 ÷ 3 = 703) | 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 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | 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 5) | 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 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 2109 a prime number?
No. 2109 = 3 × 19 × 37, so it is divisible by 3.
What are the factors of 2109?
1, 3, 19, 37, 57, 111, 703, 2109.
What is 2109 in binary?
100000111101 (hexadecimal 83D, octal 4075).
What is the square root of 2109?
About 45.9239.
What is 2109 in Roman numerals?
MMCIX.
Is 2109 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 2109?
2109 is a happy number: repeatedly adding the squares of its digits reaches 1.