BIGINT bug?

BIGINT bug?

This is a part of my code :

context is  on add row

           row.Four=2938232000000091051;  (this is BIGINT)
it's WORK
BUT WITH THIS

        Variable1 = input.Choix;    (this is BIGINT)
       row.Four=Variable1;  (this is BIGINT)

THERE IS A BUG ? Thank you^^