Compare 181 vs 191
| Property | 181 | 191 |
|---|---|---|
| Type | prime | prime |
| Unique factors | 1 | 1 |
| Total factors | 1 | 1 |
| Prime factorization | 1811 | 1911 |
| Prime factorization | 181 | 191 |
| Divisors count | 2 | 2 |
| Divisors | 1, 181 | 1, 191 |
| Number of properties | 8 | 16 |
| Additive primes | 24th | |
| Centered square primes | 6th | |
| Chen primes | 33rd | 34th |
| Class 1+ primes | 14th | |
| Dihedral primes | 5th | |
| Good primes | 16th | |
| Harmonic primes | 15th | |
| Long primes | 16th | |
| Palindromic primes | 9th | 10th |
| Pierpont primes of the 2nd kind | 14th | |
| Primes | 42nd | 43rd |
| Prime quadruplets (1st member) | 4th | |
| Prime triplets (1st member) | 13th | |
| Pythagorean primes | 19th | |
| Sexy primes (1st member) | 25th | |
| Solinas primes | 25th | |
| Sophie germain primes | 15th | |
| Super primes | 14th | |
| Thabit primes | 6th | |
| Twin primes (1st member) | 14th | |
| Twin primes (2nd member) | 13th | |
| Roman numberals | CLXXXI | CXCI |
| Base 2 | 101101012 | 101111112 |
| Base 3 | 202013 | 210023 |
| Base 4 | 23114 | 23334 |
| Base 5 | 12115 | 12315 |
| Base 6 | 5016 | 5156 |
| Base 7 | 3467 | 3627 |
| Base 8 | 2658 | 2778 |
| Base 9 | 2219 | 2329 |
| Base 10 | 18110 | 19110 |
| Base 11 | 15511 | 16411 |
| Base 12 | 13112 | 13b12 |
| Base 13 | 10c13 | 11913 |
| Base 14 | cd14 | d914 |
| Base 15 | c115 | cb15 |
| Base 16 | b516 | bf16 |