Compare 21 vs 53

Unique factors21
Total factors21
Prime factorization31 × 71531
Prime factorization3 × 753
Divisors count42
Divisors1, 3, 7, 211, 53
Number of properties118
Chen primes 15th
Class 1+ primes 10th
Good primes 7th
Isolated primes 5th
Left-truncatable primes 11th
Pierpont primes of the 2nd kind 10th
Primes 16th
Pythagorean primes 7th
Restricted right-truncatable primes 1st
Right-truncatable primes 9th
Sexy primes (1st member) 11th
Sexy primes (2nd member) 10th
Sexy prime quadrupletss (3rd member) 3rd
Sexy prime triplets (2nd member) 7th
Sexy prime triplets (3rd member) 6th
Sophie germain primes 8th
Two-sided primes 7th
Ulam primes 6th
Roman numberalsXXILIII
Base 21010121101012
Base 3210312223
Base 411143114
Base 54152035
Base 63361256
Base 73071047
Base 8258658
Base 9239589
Base 1021105310
Base 111a114911
Base 1219124512
Base 1318134113
Base 1417143b14
Base 1516153815
Base 1615163516
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