Compare 661 vs 668

Property	661	668
Type	prime	composite number
Unique factors	1	2
Total factors	1	3
Prime factorization	661¹	2² × 167¹
Prime factorization	661	2 × 2 × 167
Divisors count	2	6
Divisors	1, 661	1, 2, 4, 167, 334, 668
Number of properties	5	0
Additive primes	65th
Centered decagonal primes	8th
Primes	121st
Pythagorean primes	57th
Twin primes (2nd member)	30th
Roman numberals	DCLXI	DCLXVIII
Base 2	1010010101₂	1010011100₂
Base 3	220111₃	220202₃
Base 4	22111₄	22130₄
Base 5	10121₅	10133₅
Base 6	3021₆	3032₆
Base 7	1633₇	1643₇
Base 8	1225₈	1234₈
Base 9	814₉	822₉
Base 10	661₁₀	668₁₀
Base 11	551₁₁	558₁₁
Base 12	471₁₂	478₁₂
Base 13	3bb₁₃	3c5₁₃
Base 14	353₁₄	35a₁₄
Base 15	2e1₁₅	2e8₁₅
Base 16	295₁₆	29c₁₆