The number 77990
77990 is a composite number with 16 divisors. Its prime factorisation is 2 × 5 × 11 × 709. Divisors (16): 1, 2, 5, 10, 11, 22, 55, 110, 709, 1418, 3545, 7090, 7799, 15598, 38995, 77990.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
77990 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
77990 is composite. Its prime factorisation is
- 3
The divisors add up to 153360; without 77990 itself that is 75370, so 77990 is deficient (75370 is less than 77990). Euler's totient φ(77990) = 28320 numbers up to 77990 share no factor with it.
- 4
The digits of 77990 add up to 32, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 169 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77990 = 2 \times 5 \times 11 \times 709 \]
77990 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 153360 |
| Euler totient φ(n) | 28320 |
| Square | 6082440100 |
| Cube | 474369503399000 |
| Square root | 279.266897 |
| Digit sum / digital root | 32 / 5 |
| Collatz steps to 1 | 169 |
| Scientific notation | 7.799 × |
77990 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand nine hundred and ninety |
| Binary (base 2) | 10011000010100110 |
| Octal (base 8) | 230246 |
| Hexadecimal (base 16) | 130A6 |
| Base 3 | 10221222112 |
| As time | 77990 seconds = 21 h 39 min 50 s |
Is 77990 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (77990 ÷ 2 = 38995) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (77990 ÷ 5 = 15598) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 6) | 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 | Yes (77990 ÷ 10 = 7799) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (77990 ÷ 11 = 7090) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77990 a prime number?
No. 77990 = 2 × 5 × 11 × 709, so it is divisible by 2.
What are the factors of 77990?
1, 2, 5, 10, 11, 22, 55, 110, 709, 1418, 3545, 7090, 7799, 15598, 38995, 77990.
What is 77990 in binary?
10011000010100110 (hexadecimal 130A6, octal 230246).
What is the square root of 77990?
About 279.2669.
Is 77990 divisible by 3?
No. Its digits add up to 32, which is not a multiple of 3.
What is special about the number 77990?
It is a composite number with 16 divisors.