The number 77621
77621 is the 7629th prime number. Its only divisors are 1 and 77621.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 77621: the 7629th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
77621 is prime, so its only factors are 1 and 77621. It is the 7629th prime; the next prime is 77641 and the one before is 77617.
- 3
The divisors add up to 77622; without 77621 itself that is 1, so 77621 is deficient (1 is less than 77621). Euler's totient φ(77621) = 77620 numbers up to 77621 share no factor with it.
- 4
The digits of 77621 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 169 steps to reach 1.
77621 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 77622 |
| Euler totient φ(n) | 77620 |
| Square | 6025019641 |
| Cube | 467668049554061 |
| Square root | 278.605456 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 169 |
| Scientific notation | 7.7621 × |
77621 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand six hundred and twenty-one |
| Binary (base 2) | 10010111100110101 |
| Octal (base 8) | 227465 |
| Hexadecimal (base 16) | 12F35 |
| Base 3 | 10221110212 |
| As time | 77621 seconds = 21 h 33 min 41 s |
Is 77621 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 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 5) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77621 a prime number?
Yes. 77621 is divisible only by 1 and itself.
What are the factors of 77621?
1, 77621.
What is 77621 in binary?
10010111100110101 (hexadecimal 12F35, octal 227465).
What is the square root of 77621?
About 278.6055.
Is 77621 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 77621?
77621 is the 7629th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.