What is the numeral in «رَأَيْتُ أَحَدَ عَشَرَ طَالِبًا»?

Al-Murakkabāt — Compound Numerals, the Twelve Exception and Declining Baalbek

• Direct object in the accusative position
• Nominative subject
• Genitive after bi-
• Topic marked by ḍammah