"sad number" meaning in English

{
  "forms": [
    {
      "form": "sad numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "sad number (plural sad numbers)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Entries with translation boxes",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Terms with Polish translations",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "langcode": "en",
          "name": "Mathematics",
          "orig": "en:Mathematics",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "Any number that is not a happy number."
      ],
      "id": "en-sad_number-en-noun-1nF8PEaj",
      "links": [
        [
          "mathematics",
          "mathematics"
        ],
        [
          "happy number",
          "happy number"
        ]
      ],
      "raw_glosses": [
        "(mathematics) Any number that is not a happy number."
      ],
      "topics": [
        "mathematics",
        "sciences"
      ],
      "translations": [
        {
          "code": "pl",
          "lang": "Polish",
          "lang_code": "pl",
          "sense": "number",
          "tags": [
            "feminine"
          ],
          "word": "liczba smutna"
        }
      ]
    }
  ],
  "word": "sad number"
}

{
  "forms": [
    {
      "form": "sad numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "sad number (plural sad numbers)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "Entries with translation boxes",
        "Pages with 1 entry",
        "Pages with entries",
        "Terms with Polish translations",
        "en:Mathematics"
      ],
      "glosses": [
        "Any number that is not a happy number."
      ],
      "links": [
        [
          "mathematics",
          "mathematics"
        ],
        [
          "happy number",
          "happy number"
        ]
      ],
      "raw_glosses": [
        "(mathematics) Any number that is not a happy number."
      ],
      "topics": [
        "mathematics",
        "sciences"
      ]
    }
  ],
  "translations": [
    {
      "code": "pl",
      "lang": "Polish",
      "lang_code": "pl",
      "sense": "number",
      "tags": [
        "feminine"
      ],
      "word": "liczba smutna"
    }
  ],
  "word": "sad number"
}