Some remarks on $X(6900)$

The analysis of the LHCb data on X(6900) found in the di-$\jpsi$ system is performed using a momentum-dependent Flatt\'{e}-like parameterization. The use of the pole counting rule and spectral density function sum rule give consistent conclusions that both confining states and molecular states are possible, or it is unable to distinguish the nature of X(6900), if only the di-$\jpsi$ experimental data with current statistics are available. Nevertheless, we found that the lowest state in the di-$J/\psi$ system has very likely the same quantum numbers as X(6900), and X(6900) is probably not interpreted as a $J/\psi-\psi(2S)$ molecular state. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.