The number 7221
7221 is a composite number with 8 divisors. Its prime factorisation is 3 × 29 × 83. Divisors (8): 1, 3, 29, 83, 87, 249, 2407, 7221.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
7221 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
7221 is composite. Its prime factorisation is
- 3
The divisors add up to 10080; without 7221 itself that is 2859, so 7221 is deficient (2859 is less than 7221). Euler's totient φ(7221) = 4592 numbers up to 7221 share no factor with it.
- 4
The digits of 7221 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 57 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7221 = 3 \times 29 \times 83 \]
7221 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 10080 |
| Euler totient φ(n) | 4592 |
| Square | 52142841 |
| Cube | 376523454861 |
| Square root | 84.976467 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 57 |
| Scientific notation | 7.221 × |
7221 in other forms
| Form | Value |
|---|---|
| In words | seven thousand two hundred and twenty-one |
| Binary (base 2) | 1110000110101 |
| Octal (base 8) | 16065 |
| Hexadecimal (base 16) | 1C35 |
| Base 3 | 100220110 |
| As time | 7221 seconds = 2 h 0 min 21 s |
Is 7221 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 | Yes (7221 ÷ 3 = 2407) | 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 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 7221 a prime number?
No. 7221 = 3 × 29 × 83, so it is divisible by 3.
What are the factors of 7221?
1, 3, 29, 83, 87, 249, 2407, 7221.
What is 7221 in binary?
1110000110101 (hexadecimal 1C35, octal 16065).
What is the square root of 7221?
About 84.9765.
Is 7221 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 7221?
It is a composite number with 8 divisors.