The composite cofactor of L1803 was the product of 96-digit and 120-digit prime numbers:

96-digit prime factor:
979034292420003490028889336914657449341019932409579932298009192481134336750695323180049770154871

120-digit prime factor:
223605252530348830186244896542764047841946362997024179439955225886857946164847367747550502532827604799013828233565326309

Thanks to Carlos Pinho from SETI.USA team for performing the postprocessing. The factors have been reported to the Fibonacci project.