The number 77405
77405 is a composite number with 8 divisors. Its prime factorisation is 5 × 113 × 137. Divisors (8): 1, 5, 113, 137, 565, 685, 15481, 77405.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 77405: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
77405 is composite. Its prime factorisation is
- 3
The divisors add up to 94392; without 77405 itself that is 16987, so 77405 is deficient (16987 is less than 77405). Euler's totient φ(77405) = 60928 numbers up to 77405 share no factor with it.
- 4
The digits of 77405 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 76 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77405 = 5 \times 113 \times 137 \]
77405 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 94392 |
| Euler totient φ(n) | 60928 |
| Square | 5991534025 |
| Cube | 463774691205125 |
| Square root | 278.217541 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 76 |
| Scientific notation | 7.7405 × |
77405 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand four hundred and five |
| Binary (base 2) | 10010111001011101 |
| Octal (base 8) | 227135 |
| Hexadecimal (base 16) | 12E5D |
| Base 3 | 10221011212 |
| As time | 77405 seconds = 21 h 30 min 5 s |
Is 77405 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 | Yes (77405 ÷ 5 = 15481) | 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 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 5) | 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 9) | 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 77405 a prime number?
No. 77405 = 5 × 113 × 137, so it is divisible by 5.
What are the factors of 77405?
1, 5, 113, 137, 565, 685, 15481, 77405.
What is 77405 in binary?
10010111001011101 (hexadecimal 12E5D, octal 227135).
What is the square root of 77405?
About 278.2175.
Is 77405 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 77405?
77405 is a happy number: repeatedly adding the squares of its digits reaches 1.