The number 21098
21098 is a composite number with 16 divisors. Its prime factorisation is 2 × 7 × 11 × 137. Divisors (16): 1, 2, 7, 11, 14, 22, 77, 137, 154, 274, 959, 1507, 1918, 3014, 10549, 21098.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21098 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21098 is composite. Its prime factorisation is
- 3
The divisors add up to 39744; without 21098 itself that is 18646, so 21098 is deficient (18646 is less than 21098). Euler's totient φ(21098) = 8160 numbers up to 21098 share no factor with it.
- 4
The digits of 21098 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 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21098 = 2 \times 7 \times 11 \times 137 \]
21098 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 39744 |
| Euler totient φ(n) | 8160 |
| Square | 445125604 |
| Cube | 9391259993192 |
| Square root | 145.251506 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1098 × |
21098 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand and ninety-eight |
| Binary (base 2) | 101001001101010 |
| Octal (base 8) | 51152 |
| Hexadecimal (base 16) | 526A |
| Base 3 | 1001221102 |
| As time | 21098 seconds = 5 h 51 min 38 s |
Is 21098 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21098 ÷ 2 = 10549) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (21098 ÷ 7 = 3014) | 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 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (21098 ÷ 11 = 1918) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21098 a prime number?
No. 21098 = 2 × 7 × 11 × 137, so it is divisible by 2.
What are the factors of 21098?
1, 2, 7, 11, 14, 22, 77, 137, 154, 274, 959, 1507, 1918, 3014, 10549, 21098.
What is 21098 in binary?
101001001101010 (hexadecimal 526A, octal 51152).
What is the square root of 21098?
About 145.2515.
Is 21098 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 21098?
It is a composite number with 16 divisors.