The number 21150
21150 is a composite number with 36 divisors. Its prime factorisation is 2 × × × 47. Divisors (36): 1, 2, 3, 5, 6, 9, 10, 15, 18, 25, 30, 45, 47, 50, 75, 90 … 21150.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21150: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.
- 2
21150 is composite. Its prime factorisation is
- 3
The divisors add up to 58032; without 21150 itself that is 36882, so 21150 is abundant (36882 is more than 21150). Euler's totient φ(21150) = 5520 numbers up to 21150 share no factor with it.
- 4
The digits of 21150 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 79 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21150 = 2 \times 3^{2} \times 5^{2} \times 47 \]21150 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 36 |
| Sum of divisors | 58032 |
| Euler totient φ(n) | 5520 |
| Square | 447322500 |
| Cube | 9460870875000 |
| Square root | 145.430396 (= 15√94) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 79 |
| Scientific notation | 2.115 × |
21150 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and fifty |
| Binary (base 2) | 101001010011110 |
| Octal (base 8) | 51236 |
| Hexadecimal (base 16) | 529E |
| Base 3 | 1002000100 |
| As time | 21150 seconds = 5 h 52 min 30 s |
Is 21150 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21150 ÷ 2 = 10575) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21150 ÷ 3 = 7050) | 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 (21150 ÷ 5 = 4230) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (21150 ÷ 6 = 3525) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (21150 ÷ 9 = 2350) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21150 ÷ 10 = 2115) | 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 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21150 a prime number?
No. 21150 = 2 × × × 47, so it is divisible by 2.
What are the factors of 21150?
1, 2, 3, 5, 6, 9, 10, 15, 18, 25, 30, 45, 47, 50, 75, 90, 94, 141, 150, 225, 235, 282, 423, 450, 470, 705, 846, 1175, 1410, 2115, 2350, 3525, 4230, 7050, 10575, 21150.
What is 21150 in binary?
101001010011110 (hexadecimal 529E, octal 51236).
What is the square root of 21150?
About 145.4304, exactly 15√94.
Is 21150 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 21150?
21150 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.