The number 55621
55621 is a twin prime (55619 and 55621 are both prime) and the 5643rd prime number. Its only divisors are 1 and 55621.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 55621: a twin prime (55619 and 55621 are both prime); the 5643rd prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
55621 is prime, so its only factors are 1 and 55621. It is the 5643rd prime; the next prime is 55631 and the one before is 55619.
- 3
The divisors add up to 55622; without 55621 itself that is 1, so 55621 is deficient (1 is less than 55621). Euler's totient φ(55621) = 55620 numbers up to 55621 share no factor with it.
- 4
The digits of 55621 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 91 steps to reach 1.
55621 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 55622 |
| Euler totient φ(n) | 55620 |
| Square | 3093695641 |
| Cube | 172074445248061 |
| Square root | 235.841048 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 91 |
| Scientific notation | 5.5621 × |
55621 in other forms
| Form | Value |
|---|---|
| In words | fifty-five thousand six hundred and twenty-one |
| Binary (base 2) | 1101100101000101 |
| Octal (base 8) | 154505 |
| Hexadecimal (base 16) | D945 |
| Base 3 | 2211022001 |
| As time | 55621 seconds = 15 h 27 min 1 s |
Is 55621 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 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 1) | 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 1) | 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 55621 a prime number?
Yes. 55621 is divisible only by 1 and itself.
What are the factors of 55621?
1, 55621.
What is 55621 in binary?
1101100101000101 (hexadecimal D945, octal 154505).
What is the square root of 55621?
About 235.8410.
Is 55621 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 55621?
55621 is a twin prime (55619 and 55621 are both prime); the 5643rd prime number; a happy number: repeatedly adding the squares of its digits reaches 1.