import pandas as pd
import numpy as np
df = pd.DataFrame({'a': [1, 5, 5], 'b': [np.NaN, 7200.0, 580.0], 'c': [3, 
    20, 20]})
print((df, '\n\n'))
df['b'] = np.nan_to_num(df['b']).astype(int)
Convert float to int and leave nulls