The number 77521
77521 is the 7616th prime number. Its only divisors are 1 and 77521.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 77521: the 7616th prime number.
- 2
77521 is prime, so its only factors are 1 and 77521. It is the 7616th prime; the next prime is 77527 and the one before is 77513.
- 3
The divisors add up to 77522; without 77521 itself that is 1, so 77521 is deficient (1 is less than 77521). Euler's totient φ(77521) = 77520 numbers up to 77521 share no factor with it.
- 4
The digits of 77521 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 169 steps to reach 1.
77521 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 77522 |
| Euler totient φ(n) | 77520 |
| Square | 6009505441 |
| Cube | 465862871291761 |
| Square root | 278.425933 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 169 |
| Scientific notation | 7.7521 × |
77521 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand five hundred and twenty-one |
| Binary (base 2) | 10010111011010001 |
| Octal (base 8) | 227321 |
| Hexadecimal (base 16) | 12ED1 |
| Base 3 | 10221100011 |
| As time | 77521 seconds = 21 h 32 min 1 s |
Is 77521 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 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 | No (remainder 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 4) | 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 77521 a prime number?
Yes. 77521 is divisible only by 1 and itself.
What are the factors of 77521?
1, 77521.
What is 77521 in binary?
10010111011010001 (hexadecimal 12ED1, octal 227321).
What is the square root of 77521?
About 278.4259.
Is 77521 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 77521?
77521 is the 7616th prime number.