Compare 21 vs 47

Unique factors21
Total factors21
Prime factorization31 × 71471
Prime factorization3 × 747
Divisors count42
Divisors1, 3, 7, 211, 47
Number of properties121
Additive primes 10th
Carol primes 2nd
Chen primes 14th
Class 1+ primes 9th
Cousin primes (2nd member) 6th
Isolated primes 4th
Left-truncatable primes 10th
Long primes 6th
Lucas primes 6th
Pierpont primes of the 2nd kind 9th
Primes 15th
Prime triplets (3rd member) 7th
Safe primes 5th
Sexy primes (1st member) 10th
Sexy primes (2nd member) 9th
Sexy prime quadrupletss (2nd member) 3rd
Sexy prime triplets (1st member) 7th
Sexy prime triplets (2nd member) 6th
Solinas primes 13th
Thabit primes 5th
Ulam primes 5th
Roman numberalsXXIXLVII
Base 21010121011112
Base 3210312023
Base 411142334
Base 54151425
Base 63361156
Base 7307657
Base 8258578
Base 9239529
Base 1021104710
Base 111a114311
Base 1219123b12
Base 1318133813
Base 1417143514
Base 1516153215
Base 1615162f16
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