The number 690
690 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 5 × 23. Divisors (16): 1, 2, 3, 5, 6, 10, 15, 23, 30, 46, 69, 115, 138, 230, 345, 690.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 690: a Harshad number: divisible by its digit sum 15.
- 2
690 is composite. Its prime factorisation is
- 3
The divisors add up to 1728; without 690 itself that is 1038, so 690 is abundant (1038 is more than 690). Euler's totient φ(690) = 176 numbers up to 690 share no factor with it.
- 4
The digits of 690 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 126 steps to reach 1.
LaTeX source of the formulas on this page
\[ 690 = 2 \times 3 \times 5 \times 23 \]
690 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 1728 |
| Euler totient φ(n) | 176 |
| Square | 476100 |
| Cube | 328509000 |
| Square root | 26.267851 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 126 |
| Scientific notation | 6.9 × |
690 in other forms
| Form | Value |
|---|---|
| In words | six hundred and ninety |
| Roman numerals | DCXC |
| Binary (base 2) | 1010110010 |
| Octal (base 8) | 1262 |
| Hexadecimal (base 16) | 2B2 |
| Base 3 | 221120 |
| As time | 690 seconds = 11 min 30 s |
Is 690 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (690 ÷ 2 = 345) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (690 ÷ 3 = 230) | 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 (690 ÷ 5 = 138) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (690 ÷ 6 = 115) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (690 ÷ 10 = 69) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 690 a prime number?
No. 690 = 2 × 3 × 5 × 23, so it is divisible by 2.
What are the factors of 690?
1, 2, 3, 5, 6, 10, 15, 23, 30, 46, 69, 115, 138, 230, 345, 690.
What is 690 in binary?
1010110010 (hexadecimal 2B2, octal 1262).
What is the square root of 690?
About 26.2679.
What is 690 in Roman numerals?
DCXC.
Is 690 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 690?
690 is a Harshad number: divisible by its digit sum 15.