The Least in the Kingdom of Heaven

Jesus was quoted as saying (Matthew 11:11): "Verily I say unco you, Among them chat are born of women there hath not risen a greater than John the Baptist: not with standing he that is least in the kingdom of heaven is greater than he."
Can you believe that John the Baptist is greater than Adam, Noah, Abraham, Moses, David and many other Prophets? How many pagans had John the Baptist converted and how many followers did he have? But this is not the main point here. The question is: who was the least in the kingdom of heaven, greater than John the Baptist? For sure not Jesus, as at that time the kingdom of heaven was not yet formed, and he never claimed to be the least, i.e. the youngest one. The kingdom of heaven consists of God as the Supreme Being and all Prophets. The least or youngest one is here Prophet Muhammad [PBUH].