The number 20993
20993 is a composite number with 4 divisors. Its prime factorisation is 7 × 2999. Divisors (4): 1, 7, 2999, 20993.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20993: a semiprime: 7 × 2999, the product of two primes.
- 2
20993 is composite. Its prime factorisation is
- 3
The divisors add up to 24000; without 20993 itself that is 3007, so 20993 is deficient (3007 is less than 20993). Euler's totient φ(20993) = 17988 numbers up to 20993 share no factor with it.
- 4
The digits of 20993 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 118 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20993 = 7 \times 2999 \]
20993 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 24000 |
| Euler totient φ(n) | 17988 |
| Square | 440706049 |
| Cube | 9251742086657 |
| Square root | 144.889613 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 118 |
| Scientific notation | 2.0993 × |
20993 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand nine hundred and ninety-three |
| Binary (base 2) | 101001000000001 |
| Octal (base 8) | 51001 |
| Hexadecimal (base 16) | 5201 |
| Base 3 | 1001210112 |
| As time | 20993 seconds = 5 h 49 min 53 s |
Is 20993 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 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (20993 ÷ 7 = 2999) | 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 5) | 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 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20993 a prime number?
No. 20993 = 7 × 2999, so it is divisible by 7.
What are the factors of 20993?
1, 7, 2999, 20993.
What is 20993 in binary?
101001000000001 (hexadecimal 5201, octal 51001).
What is the square root of 20993?
About 144.8896.
Is 20993 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 20993?
20993 is a semiprime: 7 × 2999, the product of two primes.