The number 1649
1649 is a composite number with 4 divisors. Its prime factorisation is 17 × 97. Divisors (4): 1, 17, 97, 1649.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1649: a semiprime: 17 × 97, the product of two primes.
- 2
1649 is composite. Its prime factorisation is
- 3
The divisors add up to 1764; without 1649 itself that is 115, so 1649 is deficient (115 is less than 1649). Euler's totient φ(1649) = 1536 numbers up to 1649 share no factor with it.
- 4
The digits of 1649 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 29 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1649 = 17 \times 97 \]
1649 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1764 |
| Euler totient φ(n) | 1536 |
| Square | 2719201 |
| Cube | 4483962449 |
| Square root | 40.607881 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 29 |
| Scientific notation | 1.649 × |
1649 in other forms
| Form | Value |
|---|---|
| In words | one thousand six hundred and forty-nine |
| Roman numerals | MDCXLIX |
| Binary (base 2) | 11001110001 |
| Octal (base 8) | 3161 |
| Hexadecimal (base 16) | 671 |
| Base 3 | 2021002 |
| As time | 1649 seconds = 27 min 29 s |
Is 1649 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 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 5) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | 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 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1649 a prime number?
No. 1649 = 17 × 97, so it is divisible by 17.
What are the factors of 1649?
1, 17, 97, 1649.
What is 1649 in binary?
11001110001 (hexadecimal 671, octal 3161).
What is the square root of 1649?
About 40.6079.
What is 1649 in Roman numerals?
MDCXLIX.
Is 1649 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 1649?
1649 is a semiprime: 17 × 97, the product of two primes.