def convert_time(time):
    """Convert a time in seconds into the biggest unit"""
    units = [
        (24 * 60 * 60, 'days'),
        (60 * 60, 'hours'),
        (60, 'minutes'),
        (1, 'seconds'),
    ]

    if time == 0:
        return ('0', 'seconds')
    for unit in units:
        if time >= unit[0]:
            return ('{0}'.format(time // unit[0]), unit[1])