The number 21102
21102 is a composite number with 8 divisors. Its prime factorisation is 2 × 3 × 3517. Divisors (8): 1, 2, 3, 6, 3517, 7034, 10551, 21102.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21102: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 6.
- 2
21102 is composite. Its prime factorisation is
- 3
The divisors add up to 42216; without 21102 itself that is 21114, so 21102 is abundant (21114 is more than 21102). Euler's totient φ(21102) = 7032 numbers up to 21102 share no factor with it.
- 4
The digits of 21102 add up to 6, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 105 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21102 = 2 \times 3 \times 3517 \]
21102 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 42216 |
| Euler totient φ(n) | 7032 |
| Square | 445294404 |
| Cube | 9396602513208 |
| Square root | 145.265275 |
| Digit sum / digital root | 6 / 6 |
| Collatz steps to 1 | 105 |
| Scientific notation | 2.1102 × |
21102 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and two |
| Binary (base 2) | 101001001101110 |
| Octal (base 8) | 51156 |
| Hexadecimal (base 16) | 526E |
| Base 3 | 1001221120 |
| As time | 21102 seconds = 5 h 51 min 42 s |
Is 21102 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21102 ÷ 2 = 10551) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21102 ÷ 3 = 7034) | 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 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (21102 ÷ 6 = 3517) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21102 a prime number?
No. 21102 = 2 × 3 × 3517, so it is divisible by 2.
What are the factors of 21102?
1, 2, 3, 6, 3517, 7034, 10551, 21102.
What is 21102 in binary?
101001001101110 (hexadecimal 526E, octal 51156).
What is the square root of 21102?
About 145.2653.
Is 21102 divisible by 3?
Yes. Its digits add up to 6, a multiple of 3.
What is special about the number 21102?
21102 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 6.