David Wichs, 38, the man killed by a collapsing crane in lower Manhattan, was eulogized Sunday as a gifted mathematician, a loving and devoted husband, a tremendous colleague and “a supreme mensch.”

“Before you can be righteous, you have to be a mensch first,” said Haskel Lookstein, rabbi emeritus of Congregation Kehilath Jeshurun on the Upper East Side, at Wichs’ funeral, adding that Wichs “was a supreme mensch in every respect.”

Wichs’ wife, Rebecca Guttman, praised her deceased husband as “the rock of my family,” who helped them recover after the death of her father. He was “the most wonderful husband any girl could ever hope for,” she said.

Loving and down to earth, Wichs was an exemplar of always taking “the high road” and had a knack for banishing the blues in others: Whenever she was sad, Guttman recounted, her voice sometimes quavering, Wichs would “always bring me a great treat, take me on a special date or plan a trip.”

Wichs’ colleague of 15 years, Ravi Sarma, a managing partner of Tower Financial Capital, said that while the financial world measures worth by “how much money you made,” Wichs’ definition of success was solving problems and helping others.

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“He put people before profits” and always thought of others before himself, said Sarma, noting that Wichs, a Czech immigrant, was exceedingly humble and never spoke unkindly of others.

Sarma and Wichs, on several occasions, went to India, where they visited a small village in Andhra Pradesh. While Sarma complained about how the place compared unfavorably with the United States — spotty electricity, dirt roads and “no running water” — Wichs managed to see everything as “positive and charming,” Sarma recounted. Wichs’ connection with the residents there was so profound, despite their lack of a common language, that people still ask after him, Sarma said.

“There is a small village in southern India that is also weeping for David today,” he said.

Wichs engaged in a “life of giving — giving of his possessions and to causes he believed in passionately,” which included a yeshiva in Flatbush, a think tank for modern Jewish thought, and to a rabbi’s project of a “web yeshiva,” Lookstein recounted. “It’s very hard to raise funds for a web yeshiva, but David gave,” Lookstein said.