The number 21976
21976 is a composite number with 16 divisors. Its prime factorisation is × 41 × 67. Divisors (16): 1, 2, 4, 8, 41, 67, 82, 134, 164, 268, 328, 536, 2747, 5494, 10988, 21976.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21976 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21976 is composite. Its prime factorisation is
- 3
The divisors add up to 42840; without 21976 itself that is 20864, so 21976 is deficient (20864 is less than 21976). Euler's totient φ(21976) = 10560 numbers up to 21976 share no factor with it.
- 4
The digits of 21976 add up to 25, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 69 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21976 = 2^{3} \times 41 \times 67 \]21976 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 42840 |
| Euler totient φ(n) | 10560 |
| Square | 482944576 |
| Cube | 10613190002176 |
| Square root | 148.243044 (= 2√5494) |
| Digit sum / digital root | 25 / 7 |
| Collatz steps to 1 | 69 |
| Scientific notation | 2.1976 × |
21976 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand nine hundred and seventy-six |
| Binary (base 2) | 101010111011000 |
| Octal (base 8) | 52730 |
| Hexadecimal (base 16) | 55D8 |
| Base 3 | 1010010221 |
| As time | 21976 seconds = 6 h 6 min 16 s |
Is 21976 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21976 ÷ 2 = 10988) | 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 | Yes (21976 ÷ 4 = 5494) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 | Yes (21976 ÷ 8 = 2747) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 6) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21976 a prime number?
No. 21976 = × 41 × 67, so it is divisible by 2.
What are the factors of 21976?
1, 2, 4, 8, 41, 67, 82, 134, 164, 268, 328, 536, 2747, 5494, 10988, 21976.
What is 21976 in binary?
101010111011000 (hexadecimal 55D8, octal 52730).
What is the square root of 21976?
About 148.2430, exactly 2√5494.
Is 21976 divisible by 3?
No. Its digits add up to 25, which is not a multiple of 3.
What is special about the number 21976?
It is a composite number with 16 divisors.