The number 76421
76421 is a twin prime (76421 and 76423 are both prime) and the 7518th prime number. Its only divisors are 1 and 76421.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 76421: a twin prime (76421 and 76423 are both prime); the 7518th prime number.
- 2
76421 is prime, so its only factors are 1 and 76421. It is the 7518th prime; the next prime is 76423 and the one before is 76403.
- 3
The divisors add up to 76422; without 76421 itself that is 1, so 76421 is deficient (1 is less than 76421). Euler's totient φ(76421) = 76420 numbers up to 76421 share no factor with it.
- 4
The digits of 76421 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 107 steps to reach 1.
76421 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 76422 |
| Euler totient φ(n) | 76420 |
| Square | 5840169241 |
| Cube | 446311573566461 |
| Square root | 276.443484 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 107 |
| Scientific notation | 7.6421 × |
76421 in other forms
| Form | Value |
|---|---|
| In words | seventy-six thousand four hundred and twenty-one |
| Binary (base 2) | 10010101010000101 |
| Octal (base 8) | 225205 |
| Hexadecimal (base 16) | 12A85 |
| Base 3 | 10212211102 |
| As time | 76421 seconds = 21 h 13 min 41 s |
Is 76421 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 2) | 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 2) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 76421 a prime number?
Yes. 76421 is divisible only by 1 and itself.
What are the factors of 76421?
1, 76421.
What is 76421 in binary?
10010101010000101 (hexadecimal 12A85, octal 225205).
What is the square root of 76421?
About 276.4435.
Is 76421 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 76421?
76421 is a twin prime (76421 and 76423 are both prime); the 7518th prime number.