Compare 21 vs 61

Unique factors21
Total factors21
Prime factorization31 × 71611
Prime factorization3 × 761
Divisors count42
Divisors1, 3, 7, 211, 61
Number of properties112
Additive primes 11th
Centered decagonal primes 3rd
Centered square primes 4th
Cuban primes 1 4th
Long primes 8th
Primes 18th
Pythagorean primes 8th
Sexy primes (1st member) 12th
Sexy prime quadrupletss (1st member) 4th
Sexy prime triplets (1st member) 8th
Solinas primes 15th
Twin primes (2nd member) 7th
Roman numberalsXXILXI
Base 21010121111012
Base 3210320213
Base 411143314
Base 54152215
Base 63361416
Base 73071157
Base 8258758
Base 9239679
Base 1021106110
Base 111a115611
Base 1219125112
Base 1318134913
Base 1417144514
Base 1516154115
Base 1615163d16
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