The number 61221
61221 is a composite number with 4 divisors. Its prime factorisation is 3 × 20407. Divisors (4): 1, 3, 20407, 61221.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 61221: a semiprime: 3 × 20407, the product of two primes.
- 2
61221 is composite. Its prime factorisation is
- 3
The divisors add up to 81632; without 61221 itself that is 20411, so 61221 is deficient (20411 is less than 61221). Euler's totient φ(61221) = 40812 numbers up to 61221 share no factor with it.
- 4
The digits of 61221 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 179 steps to reach 1.
LaTeX source of the formulas on this page
\[ 61221 = 3 \times 20407 \]
61221 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 81632 |
| Euler totient φ(n) | 40812 |
| Square | 3748010841 |
| Cube | 229456971696861 |
| Square root | 247.428778 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 179 |
| Scientific notation | 6.1221 × |
61221 in other forms
| Form | Value |
|---|---|
| In words | sixty-one thousand two hundred and twenty-one |
| Binary (base 2) | 1110111100100101 |
| Octal (base 8) | 167445 |
| Hexadecimal (base 16) | EF25 |
| Base 3 | 10002222110 |
| As time | 61221 seconds = 17 h 0 min 21 s |
Is 61221 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 (61221 ÷ 3 = 20407) | 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 6) | 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 6) | 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 61221 a prime number?
No. 61221 = 3 × 20407, so it is divisible by 3.
What are the factors of 61221?
1, 3, 20407, 61221.
What is 61221 in binary?
1110111100100101 (hexadecimal EF25, octal 167445).
What is the square root of 61221?
About 247.4288.
Is 61221 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 61221?
61221 is a semiprime: 3 × 20407, the product of two primes.