The number 21010
21010 is a composite number with 16 divisors. Its prime factorisation is 2 × 5 × 11 × 191. Divisors (16): 1, 2, 5, 10, 11, 22, 55, 110, 191, 382, 955, 1910, 2101, 4202, 10505, 21010.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21010 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21010 is composite. Its prime factorisation is
- 3
The divisors add up to 41472; without 21010 itself that is 20462, so 21010 is deficient (20462 is less than 21010). Euler's totient φ(21010) = 7600 numbers up to 21010 share no factor with it.
- 4
The digits of 21010 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 149 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21010 = 2 \times 5 \times 11 \times 191 \]
21010 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 41472 |
| Euler totient φ(n) | 7600 |
| Square | 441420100 |
| Cube | 9274236301000 |
| Square root | 144.948267 |
| Digit sum / digital root | 4 / 4 |
| Collatz steps to 1 | 149 |
| Scientific notation | 2.101 × |
21010 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand and ten |
| Binary (base 2) | 101001000010010 |
| Octal (base 8) | 51022 |
| Hexadecimal (base 16) | 5212 |
| Base 3 | 1001211011 |
| As time | 21010 seconds = 5 h 50 min 10 s |
Is 21010 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21010 ÷ 2 = 10505) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (21010 ÷ 5 = 4202) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 2) | 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 | Yes (21010 ÷ 10 = 2101) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (21010 ÷ 11 = 1910) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21010 a prime number?
No. 21010 = 2 × 5 × 11 × 191, so it is divisible by 2.
What are the factors of 21010?
1, 2, 5, 10, 11, 22, 55, 110, 191, 382, 955, 1910, 2101, 4202, 10505, 21010.
What is 21010 in binary?
101001000010010 (hexadecimal 5212, octal 51022).
What is the square root of 21010?
About 144.9483.
Is 21010 divisible by 3?
No. Its digits add up to 4, which is not a multiple of 3.
What is special about the number 21010?
It is a composite number with 16 divisors.