def int_to_ip(value):
    """
    >>> int_to_ip(None)
    ''
    >>> int_to_ip(0)
    ''
    >>> int_to_ip(-1)
    '-1'
    >>> int_to_ip(16909060)
    '1.2.3.4'
    """
    if not value:
        return ''
    if value < 0:
        return str(value)
    return '.'.join((
        str((value >> 24) & 0xFF),
        str((value >> 16) & 0xFF),
        str((value >> 8) & 0xFF),
        str(value & 0xFF)))