Compare 19 vs 21

Unique factors12
Total factors12
Prime factorization19131 × 71
Prime factorization193 × 7
Divisors count24
Divisors1, 191, 3, 7, 21
Number of properties181
Centered triangular primes1st 
Chen primes8th 
Cousin primes (1st member)4th 
Cuban primes 12nd 
Happy primes3rd 
Long primes3rd 
Pierpont primes7th 
Prime quadruplets (4th member)2nd 
Prime quintuplet 1s (5th member)1st 
Prime quintuplet 2s (4th member)2nd 
Prime sextuplets (5th member)1st 
Prime triplets (2nd member)5th 
Prime triplets (3rd member)4th 
Semiprimes 7th
Sexy primes (2nd member)4th 
Sexy prime triplets (3rd member)2nd 
Solinas primes7th 
Twin primes (2nd member)4th 
Roman numberalsXIXXXI
Base 2100112101012
Base 320132103
Base 410341114
Base 5345415
Base 6316336
Base 7257307
Base 8238258
Base 9219239
Base 1019102110
Base 1118111a11
Base 1217121912
Base 1316131813
Base 1415141714
Base 1514151615
Base 1613161516
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