The number 1995
1995 is a composite number with 16 divisors. Its prime factorisation is 3 × 5 × 7 × 19. Divisors (16): 1, 3, 5, 7, 15, 19, 21, 35, 57, 95, 105, 133, 285, 399, 665, 1995.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1995: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
1995 is composite. Its prime factorisation is
- 3
The divisors add up to 3840; without 1995 itself that is 1845, so 1995 is deficient (1845 is less than 1995). Euler's totient φ(1995) = 864 numbers up to 1995 share no factor with it.
- 4
The digits of 1995 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 50 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1995 = 3 \times 5 \times 7 \times 19 \]
1995 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 3840 |
| Euler totient φ(n) | 864 |
| Square | 3980025 |
| Cube | 7940149875 |
| Square root | 44.665423 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 50 |
| Scientific notation | 1.995 × |
1995 in other forms
| Form | Value |
|---|---|
| In words | one thousand nine hundred and ninety-five |
| Roman numerals | MCMXCV |
| Binary (base 2) | 11111001011 |
| Octal (base 8) | 3713 |
| Hexadecimal (base 16) | 7CB |
| Base 3 | 2201220 |
| As time | 1995 seconds = 33 min 15 s |
Is 1995 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 (1995 ÷ 3 = 665) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (1995 ÷ 5 = 399) | 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 | Yes (1995 ÷ 7 = 285) | 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 3) | 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 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1995 a prime number?
No. 1995 = 3 × 5 × 7 × 19, so it is divisible by 3.
What are the factors of 1995?
1, 3, 5, 7, 15, 19, 21, 35, 57, 95, 105, 133, 285, 399, 665, 1995.
What is 1995 in binary?
11111001011 (hexadecimal 7CB, octal 3713).
What is the square root of 1995?
About 44.6654.
What is 1995 in Roman numerals?
MCMXCV.
Is 1995 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 1995?
1995 is a happy number: repeatedly adding the squares of its digits reaches 1.