The Mantra No. 177 of "Shree Vishnu-SahasraNam" is:
ॐ अनिर्देश्यवपुषे नमः
OM anirdeshyavapuShe namaH
Tika by OM VishnuPad Parashara Bhatta MahAcharya (Shree Ramanuja-Sampradaya): Shad-Guna-Rupa of Bhagavan Shree Vishnu (The Rupa of Bhagavan Shree Vishnu Absolutely Rich in Six Divine Gunas) is beyond description and Unparalleled.
Nevertheless, Bhagavan Shree Vishnu appears before His devotees in the Rupa they (devotees) dream to worship and see!
Tika by Shree ShankarAcharya: Swarupa of Bhagavan Shree Vishnu cannot be described to others, because the Existence of Bhagavan Shree Vishnu is out of common sense experience and must be realized.
Like Jyotish which is self-luminous and absolute. Such Jyotish is beyond verbal description and must be experienced by jiva.***
***Note by Vishnudut1926: Shree ShankarAcharya explains Siddhanta "Words can't reach Him" from "Shree Katha-Upanishad", 6.12 here:
Translation: "Not by Speech or mind is one able to know Him, nor by the eye, how then is He to be obtained from any, save the one (Guru) who knows that the Lord is "The Great He Is". (translation cited from UPANISHADS WITH SHREE SHREEMAD MADHVACARYA COMMENTARIES: Ishavasya, Kena, Katha, Prashna, Mundaka, Manduka, Allahabad, 1911)
In His Tika to "Shree Katha-Upanishad", 6.12 OM VishnuPad MadhvAcharya (Shree Madhva-Sampradaya) writes about Absolute Excellence of Bhagavan Shree Vishnu, that is the explanation is the same as in the above-mentioned Tika by OM VishnuPad Parashara Bhatta MahAcharya about Excellence of Shad-Gunas of Bhagavan Shree Vishnu:
Vishnudut1926, Moscow, January 2017