The number 21763
21763 is a composite number with 4 divisors. Its prime factorisation is 7 × 3109. Divisors (4): 1, 7, 3109, 21763.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21763: a semiprime: 7 × 3109, the product of two primes.
- 2
21763 is composite. Its prime factorisation is
- 3
The divisors add up to 24880; without 21763 itself that is 3117, so 21763 is deficient (3117 is less than 21763). Euler's totient φ(21763) = 18648 numbers up to 21763 share no factor with it.
- 4
The digits of 21763 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 180 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21763 = 7 \times 3109 \]
21763 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 24880 |
| Euler totient φ(n) | 18648 |
| Square | 473628169 |
| Cube | 10307569841947 |
| Square root | 147.522880 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 180 |
| Scientific notation | 2.1763 × |
21763 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand seven hundred and sixty-three |
| Binary (base 2) | 101010100000011 |
| Octal (base 8) | 52403 |
| Hexadecimal (base 16) | 5503 |
| Base 3 | 1002212001 |
| As time | 21763 seconds = 6 h 2 min 43 s |
Is 21763 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 3) | 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 | Yes (21763 ÷ 7 = 3109) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21763 a prime number?
No. 21763 = 7 × 3109, so it is divisible by 7.
What are the factors of 21763?
1, 7, 3109, 21763.
What is 21763 in binary?
101010100000011 (hexadecimal 5503, octal 52403).
What is the square root of 21763?
About 147.5229.
Is 21763 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 21763?
21763 is a semiprime: 7 × 3109, the product of two primes.