public BigInteger bigIntegerValue() {
        BigInteger v = BigInteger.valueOf(value);
        if (value < 0L) {
            v = v.and(MASK);
        }
        return v;
    }
Returns the value of this {@code UnsignedLong} as a {@link BigInteger}.

@return a BigInteger representing the unsigned long value
clickhouse-data/src/main/java/com/clickhouse/data/value/UnsignedLong.java