Saith
rhif
Rhif rhwng chwech ac wyth yw saith (7). Mae'n rhif cysefin.
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| Enghraifft o'r canlynol | rhif 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  |
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