The number 21073
21073 is a composite number with 4 divisors. Its prime factorisation is 13 × 1621. Divisors (4): 1, 13, 1621, 21073.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21073: a Harshad number: divisible by its digit sum 13; a semiprime: 13 × 1621, the product of two primes.
- 2
21073 is composite. Its prime factorisation is
- 3
The divisors add up to 22708; without 21073 itself that is 1635, so 21073 is deficient (1635 is less than 21073). Euler's totient φ(21073) = 19440 numbers up to 21073 share no factor with it.
- 4
The digits of 21073 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 79 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21073 = 13 \times 1621 \]
21073 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 22708 |
| Euler totient φ(n) | 19440 |
| Square | 444071329 |
| Cube | 9357915116017 |
| Square root | 145.165423 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 79 |
| Scientific notation | 2.1073 × |
21073 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand and seventy-three |
| Binary (base 2) | 101001001010001 |
| Octal (base 8) | 51121 |
| Hexadecimal (base 16) | 5251 |
| Base 3 | 1001220111 |
| As time | 21073 seconds = 5 h 51 min 13 s |
Is 21073 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 3) | 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 | 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 1) | 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 | No (remainder 3) | 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21073 a prime number?
No. 21073 = 13 × 1621, so it is divisible by 13.
What are the factors of 21073?
1, 13, 1621, 21073.
What is 21073 in binary?
101001001010001 (hexadecimal 5251, octal 51121).
What is the square root of 21073?
About 145.1654.
Is 21073 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 21073?
21073 is a Harshad number: divisible by its digit sum 13; a semiprime: 13 × 1621, the product of two primes.