The number 790
790 is a composite number with 8 divisors. Its prime factorisation is 2 × 5 × 79. Divisors (8): 1, 2, 5, 10, 79, 158, 395, 790.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 790: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
790 is composite. Its prime factorisation is
- 3
The divisors add up to 1440; without 790 itself that is 650, so 790 is deficient (650 is less than 790). Euler's totient φ(790) = 312 numbers up to 790 share no factor with it.
- 4
The digits of 790 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 77 steps to reach 1.
LaTeX source of the formulas on this page
\[ 790 = 2 \times 5 \times 79 \]
790 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 1440 |
| Euler totient φ(n) | 312 |
| Square | 624100 |
| Cube | 493039000 |
| Square root | 28.106939 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 77 |
| Scientific notation | 7.9 × |
790 in other forms
| Form | Value |
|---|---|
| In words | seven hundred and ninety |
| Roman numerals | DCCXC |
| Binary (base 2) | 1100010110 |
| Octal (base 8) | 1426 |
| Hexadecimal (base 16) | 316 |
| Base 3 | 1002021 |
| As time | 790 seconds = 13 min 10 s |
Is 790 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (790 ÷ 2 = 395) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (790 ÷ 5 = 158) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 6) | 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 | Yes (790 ÷ 10 = 79) | 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 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 790 a prime number?
No. 790 = 2 × 5 × 79, so it is divisible by 2.
What are the factors of 790?
1, 2, 5, 10, 79, 158, 395, 790.
What is 790 in binary?
1100010110 (hexadecimal 316, octal 1426).
What is the square root of 790?
About 28.1069.
What is 790 in Roman numerals?
DCCXC.
Is 790 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 790?
790 is a happy number: repeatedly adding the squares of its digits reaches 1.