The number 77875
77875 is a composite number with 16 divisors. Its prime factorisation is × 7 × 89. Divisors (16): 1, 5, 7, 25, 35, 89, 125, 175, 445, 623, 875, 2225, 3115, 11125, 15575, 77875.
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How to work it out
- 1
What is special about 77875: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
77875 is composite. Its prime factorisation is
- 3
The divisors add up to 112320; without 77875 itself that is 34445, so 77875 is deficient (34445 is less than 77875). Euler's totient φ(77875) = 52800 numbers up to 77875 share no factor with it.
- 4
The digits of 77875 add up to 34, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 169 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77875 = 5^{3} \times 7 \times 89 \]77875 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 112320 |
| Euler totient φ(n) | 52800 |
| Square | 6064515625 |
| Cube | 472274154296875 |
| Square root | 279.060925 (= 5√3115) |
| Digit sum / digital root | 34 / 7 |
| Collatz steps to 1 | 169 |
| Scientific notation | 7.7875 × |
77875 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand eight hundred and seventy-five |
| Binary (base 2) | 10011000000110011 |
| Octal (base 8) | 230063 |
| Hexadecimal (base 16) | 13033 |
| Base 3 | 10221211021 |
| As time | 77875 seconds = 21 h 37 min 55 s |
Is 77875 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (77875 ÷ 5 = 15575) | 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 | Yes (77875 ÷ 7 = 11125) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77875 a prime number?
No. 77875 = × 7 × 89, so it is divisible by 5.
What are the factors of 77875?
1, 5, 7, 25, 35, 89, 125, 175, 445, 623, 875, 2225, 3115, 11125, 15575, 77875.
What is 77875 in binary?
10011000000110011 (hexadecimal 13033, octal 230063).
What is the square root of 77875?
About 279.0609, exactly 5√3115.
Is 77875 divisible by 3?
No. Its digits add up to 34, which is not a multiple of 3.
What is special about the number 77875?
77875 is a happy number: repeatedly adding the squares of its digits reaches 1.