Before the 20th century, definitions of primality were inconsistent, and significant mathematicians such as Goldbach, Lambert, Legendre, Cayley, and Kronecker wrote that 1 was prime.
Sebelum abad ke-20, definisi bilangan prima tidak konsisten, dan matematikawan hebat seperti Goldbach, Lambert, Legendre, Cayley, dan Kronecker menulis bahwa 1 adalah bilangan prima.