The number 1990
1990 is a composite number with 8 divisors. Its prime factorisation is 2 × 5 × 199. Divisors (8): 1, 2, 5, 10, 199, 398, 995, 1990.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
1990 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
1990 is composite. Its prime factorisation is
- 3
The divisors add up to 3600; without 1990 itself that is 1610, so 1990 is deficient (1610 is less than 1990). Euler's totient φ(1990) = 792 numbers up to 1990 share no factor with it.
- 4
The digits of 1990 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 24 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1990 = 2 \times 5 \times 199 \]
1990 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 3600 |
| Euler totient φ(n) | 792 |
| Square | 3960100 |
| Cube | 7880599000 |
| Square root | 44.609416 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 24 |
| Scientific notation | 1.99 × |
1990 in other forms
| Form | Value |
|---|---|
| In words | one thousand nine hundred and ninety |
| Roman numerals | MCMXC |
| Binary (base 2) | 11111000110 |
| Octal (base 8) | 3706 |
| Hexadecimal (base 16) | 7C6 |
| Base 3 | 2201201 |
| As time | 1990 seconds = 33 min 10 s |
Is 1990 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1990 ÷ 2 = 995) | 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 (1990 ÷ 5 = 398) | 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 2) | 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 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (1990 ÷ 10 = 199) | 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 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1990 a prime number?
No. 1990 = 2 × 5 × 199, so it is divisible by 2.
What are the factors of 1990?
1, 2, 5, 10, 199, 398, 995, 1990.
What is 1990 in binary?
11111000110 (hexadecimal 7C6, octal 3706).
What is the square root of 1990?
About 44.6094.
What is 1990 in Roman numerals?
MCMXC.
Is 1990 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 1990?
It is a composite number with 8 divisors.