The number 77409
77409 is a composite number with 16 divisors. Its prime factorisation is × 47 × 61. Divisors (16): 1, 3, 9, 27, 47, 61, 141, 183, 423, 549, 1269, 1647, 2867, 8601, 25803, 77409.
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How to work it out
- 1
What is special about 77409: a Harshad number: divisible by its digit sum 27.
- 2
77409 is composite. Its prime factorisation is
- 3
The divisors add up to 119040; without 77409 itself that is 41631, so 77409 is deficient (41631 is less than 77409). Euler's totient φ(77409) = 49680 numbers up to 77409 share no factor with it.
- 4
The digits of 77409 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 200 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77409 = 3^{3} \times 47 \times 61 \]77409 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 119040 |
| Euler totient φ(n) | 49680 |
| Square | 5992153281 |
| Cube | 463846593328929 |
| Square root | 278.224729 (= 3√8601) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 200 |
| Scientific notation | 7.7409 × |
77409 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand four hundred and nine |
| Binary (base 2) | 10010111001100001 |
| Octal (base 8) | 227141 |
| Hexadecimal (base 16) | 12E61 |
| Base 3 | 10221012000 |
| As time | 77409 seconds = 21 h 30 min 9 s |
Is 77409 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 | Yes (77409 ÷ 3 = 25803) | 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 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | 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 | Yes (77409 ÷ 9 = 8601) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77409 a prime number?
No. 77409 = × 47 × 61, so it is divisible by 3.
What are the factors of 77409?
1, 3, 9, 27, 47, 61, 141, 183, 423, 549, 1269, 1647, 2867, 8601, 25803, 77409.
What is 77409 in binary?
10010111001100001 (hexadecimal 12E61, octal 227141).
What is the square root of 77409?
About 278.2247, exactly 3√8601.
Is 77409 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 77409?
77409 is a Harshad number: divisible by its digit sum 27.