Rhif rhwng chwech ac wyth yw saith (7). Mae'n rhif cysefin.

Saith
Enghraifft o'r canlynolrhif cysefin, Mersenne prime, rhif naturiol, odrhif, centered hexagonal number, centered octahedral number, heptagonal number, hexagonal pyramidal number, Woodall number, double Mersenne number, Cantor number, Mersenne number, factorial prime, non-negative integer, harshad number, primorial prime, Euclid number Edit this on Wikidata
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