The number 77531
77531 is a composite number with 8 divisors. Its prime factorisation is 31 × 41 × 61. Divisors (8): 1, 31, 41, 61, 1271, 1891, 2501, 77531.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 77531: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
77531 is composite. Its prime factorisation is
- 3
The divisors add up to 83328; without 77531 itself that is 5797, so 77531 is deficient (5797 is less than 77531). Euler's totient φ(77531) = 72000 numbers up to 77531 share no factor with it.
- 4
The digits of 77531 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
\[ 77531 = 31 \times 41 \times 61 \]
77531 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 83328 |
| Euler totient φ(n) | 72000 |
| Square | 6011055961 |
| Cube | 466043179712291 |
| Square root | 278.443890 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 76 |
| Scientific notation | 7.7531 × |
77531 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand five hundred and thirty-one |
| Binary (base 2) | 10010111011011011 |
| Octal (base 8) | 227333 |
| Hexadecimal (base 16) | 12EDB |
| Base 3 | 10221100112 |
| As time | 77531 seconds = 21 h 32 min 11 s |
Is 77531 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 3) | 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 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 3) | 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 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77531 a prime number?
No. 77531 = 31 × 41 × 61, so it is divisible by 31.
What are the factors of 77531?
1, 31, 41, 61, 1271, 1891, 2501, 77531.
What is 77531 in binary?
10010111011011011 (hexadecimal 12EDB, octal 227333).
What is the square root of 77531?
About 278.4439.
Is 77531 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 77531?
77531 is a happy number: repeatedly adding the squares of its digits reaches 1.