Number dictionary · Exact arithmetic
842: factors and number facts
eight hundred forty-two is an even number and is composite. Its 4 positive divisors form 2 factor pairs.
Number JD Editorial Team · Updated 2026-10-08
- In words
- eight hundred forty-two
- Roman numeral
- DCCCXLII
- Prime factorization
- 2 × 421
- Digital root
- 5
All factors of 842
A positive factor divides 842 with no remainder. In ascending order, the complete list is:
1, 2, 421, 842
Factor pairs
- 1 × 842 = 842
- 2 × 421 = 842
Each pair describes an arrangement of 842 items into equal rows. The pairs have different row and column counts; 842 cannot make a square array of whole items.
Divisor totals
- Positive divisors
- 4
- Sum of all divisors
- 1266
- Sum excluding 842
- 424
- Classification
- deficient
842 is deficient because its proper divisors add to 424, which is less than 842.
Prime factorization of 842
842 = 2 × 421
Repeated division, step by step
- 842 ÷ 2 = 421
- 421 ÷ 421 = 1
Multiply the prime divisors in these steps to reconstruct 842. Each prime in this factorization occurs once. The divisor-count calculation is (1 + 1) × (1 + 1) = 4.
The preceding prime is 839. The next larger prime is 853. The factor list above explains why 842 is composite.
Learn the factorization method842 in words, Roman numerals and other bases
| Representation | Value |
|---|---|
| English (US style) | eight hundred forty-two |
| Roman numeral | DCCCXLII |
| Binary (base 2) | 1101001010 |
| Octal (base 8) | 1512 |
| Decimal (base 10) | 842 |
| Hexadecimal (base 16) | 34A |
Check the binary conversion
Read 1101001010 from right to left using place values 1, 2, 4, 8 and successive powers of two. Keep the values whose bit is 1:
512 + 256 + 64 + 8 + 2 = 842
Check the hexadecimal conversion
3 × 16^2 + 4 × 16^1 + 10 × 16^0 = 842
Hexadecimal uses A through F for digit values 10 through 15. These notations represent the same quantity; changing the base does not change the integer.
Square, cube and square root of 842
- 842 squared
- 842 × 842 = 708,964
- 842 cubed
- 842 × 842 × 842 = 596,947,688
- Square root
- ≈ 29.017236
- Simplified radical
- √842
842 lies between 841 (29²) and 900 (30²), so it is not a perfect square. It is not a perfect cube.
842 is not triangular: no positive whole-number k satisfies k(k + 1) / 2 = 842.
Distinguish a square from a square rootMultiplication table for 842
These are the first twelve positive multiples. Unlike the finite factor list, the sequence of multiples continues without an upper limit.
Divisibility checks
| Divide by | Whole quotient | Remainder | Divides exactly? |
|---|---|---|---|
| 2 | 421 | 0 | Yes |
| 3 | 280 | 2 | No |
| 4 | 210 | 2 | No |
| 5 | 168 | 2 | No |
| 6 | 140 | 2 | No |
| 7 | 120 | 2 | No |
| 8 | 105 | 2 | No |
| 9 | 93 | 5 | No |
| 10 | 84 | 2 | No |
| 11 | 76 | 6 | No |
| 12 | 70 | 2 | No |
For example, 842 = 7 × 120 + 2. A remainder of zero is what makes a divisor a factor.
Digit sum and digital root of 842
842 contains 3 decimal digits. Its digit sum is 8 + 4 + 2 = 14.
- 842: 8 + 4 + 2 = 14
- 14: 1 + 4 = 5
The digital root is 5. Reversing its digits gives 248; it is not a decimal palindrome. Digit patterns depend on the notation being used.
Digital-root arithmetic always finishes at a single digit for a positive integer. Some numerology methods stop at 11, 22 or 33 instead; that is a separate interpretive convention.
Fractions and a worked comparison
As a fraction of 100, 842/100 simplifies to 421/50 by dividing both terms by their greatest common divisor, 2. Its decimal value is 8.42. Because the numerator exceeds the denominator, this value is greater than one.
The greatest common divisor of 842 and 12 is 2. Their least common multiple is 5052. The identity GCD × LCM = 842 × 12 = 10104 checks both results.
Work through GCF and LCMQuestions about 842
What are the factors of 842?
The positive factors are 1, 2, 421, 842. There are 4 factors, including 1 and 842.
Is 842 a prime number?
No. 842 is composite: 2 × 421 = 842.
How do you write 842 in Roman numerals?
842 is DCCCXLII in standard subtractive Roman numeral notation.
What is the binary representation of 842?
842 in decimal is 1101001010 in base 2. Adding its active place values gives 512 + 256 + 64 + 8 + 2 = 842.
Methods and reference definitions
Number JD calculates each result from the integer on this page. Positive factors are enumerated in pairs; repeated division gives the prime factorization; place values verify base conversions. Decimal square roots are rounded to six places when irrational.
NUMBER JOURNAL / JD
A reflective note on 842
Meaning varies by tradition and personal experience. One sighting is not evidence of what will happen next.
The digits of 842 add to 14. That arithmetic result is separate from the cultural symbolism of the pattern. If this number matters to you, write down what you noticed and choose one grounded action rather than treating the sighting as a prediction.