The number 21049
21049 is a composite number with 8 divisors. Its prime factorisation is 7 × 31 × 97. Divisors (8): 1, 7, 31, 97, 217, 679, 3007, 21049.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21049 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21049 is composite. Its prime factorisation is
- 3
The divisors add up to 25088; without 21049 itself that is 4039, so 21049 is deficient (4039 is less than 21049). Euler's totient φ(21049) = 17280 numbers up to 21049 share no factor with it.
- 4
The digits of 21049 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 180 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21049 = 7 \times 31 \times 97 \]
21049 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 25088 |
| Euler totient φ(n) | 17280 |
| Square | 443060401 |
| Cube | 9325978380649 |
| Square root | 145.082735 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 180 |
| Scientific notation | 2.1049 × |
21049 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand and forty-nine |
| Binary (base 2) | 101001000111001 |
| Octal (base 8) | 51071 |
| Hexadecimal (base 16) | 5239 |
| Base 3 | 1001212121 |
| As time | 21049 seconds = 5 h 50 min 49 s |
Is 21049 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 4) | 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 | Yes (21049 ÷ 7 = 3007) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | 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 6) | 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 21049 a prime number?
No. 21049 = 7 × 31 × 97, so it is divisible by 7.
What are the factors of 21049?
1, 7, 31, 97, 217, 679, 3007, 21049.
What is 21049 in binary?
101001000111001 (hexadecimal 5239, octal 51071).
What is the square root of 21049?
About 145.0827.
Is 21049 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 21049?
It is a composite number with 8 divisors.