Compare 7 vs 28

Typeprimecomposite number
Unique factors12
Total factors13
Prime factorization7122 × 71
Prime factorization72 × 2 × 7
Divisors count26
Divisors1, 71, 2, 4, 7, 14, 28
Number of properties370
Additive primes4th 
Carol primes1st 
Chen primes4th 
Class 1+ primes4th 
Cousin primes (1st member)2nd 
Cousin primes (2nd member)1st 
Cuban primes 11st 
Double mersenne primes1st 
Euclid primes3rd 
Factorial primes4th 
Happy primes1st 
Kynea primes2nd 
Left-truncatable primes4th 
Long primes1st 
Lucas primes3rd 
Lucky primes2nd 
Mersenne primes2nd 
Multiplicative primes4th 
Palindromic primes4th 
Pierpont primes4th 
Pierpont primes of the 2nd kind4th 
Prime quadruplets (2nd member)1st 
Prime quintuplet 1s (1st member)1st 
Prime quintuplet 2s (2nd member)1st 
Prime sextuplets (1st member)1st 
Prime triplets (1st member)2nd 
Prime triplets (2nd member)1st 
Right-truncatable primes4th 
Safe primes2nd 
Sexy primes (1st member)2nd 
Sexy prime triplets (1st member)2nd 
Solinas primes3rd 
Thabit primes of the 2nd kind1st 
Twin primes (2nd member)2nd 
Two-sided primes4th 
Woodall primes1st 
Roman numberalsVIIXXVIII
Base 21112111002
Base 321310013
Base 41341304
Base 51251035
Base 6116446
Base 7107407
Base 878348
Base 979319
Base 107102810
Base 117112611
Base 127122412
Base 137132213
Base 147142014
Base 157151d15
Base 167161c16
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