Please help me fix this code! When I run it it says that "length is not defined"

word1 = "sesquipedalian"

word2 = "sesquiannual"
length_of_word1 = length(word1)

length_of_word2 = length(word2)

test_number = 4298374272384726348726348726348234

if length_of_word1>length_of_word2:
    test_number += length_of_word1%3
else:
    test_number -= length_of_word1%3

print test_number