"happy number" meaning in English

{
  "forms": [
    {
      "form": "happy numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "happy number (plural happy numbers)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "antonyms": [
        {
          "word": "sad number"
        },
        {
          "word": "unhappy number"
        }
      ],
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Mathematics",
          "orig": "en:Mathematics",
          "parents": [
            "Formal sciences",
            "Sciences",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "text": "13 is a happy number because 1² + 3² is 10, and 1² + 0² is 1.",
          "type": "example"
        }
      ],
      "glosses": [
        "Any number that eventually reaches 1 after some number of iterations of replacing each of its digits by the sum of that digit's squares."
      ],
      "id": "en-happy_number-en-noun-7zlKWk7V",
      "links": [
        [
          "mathematics",
          "mathematics"
        ],
        [
          "iteration",
          "iteration"
        ],
        [
          "digit",
          "digit"
        ],
        [
          "sum",
          "sum"
        ],
        [
          "square",
          "square"
        ]
      ],
      "raw_glosses": [
        "(mathematics) Any number that eventually reaches 1 after some number of iterations of replacing each of its digits by the sum of that digit's squares."
      ],
      "topics": [
        "mathematics",
        "sciences"
      ]
    }
  ],
  "word": "happy number"
}

{
  "forms": [
    {
      "form": "happy numbers",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "happy number (plural happy numbers)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "antonyms": [
        {
          "word": "sad number"
        },
        {
          "word": "unhappy number"
        }
      ],
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with usage examples",
        "en:Mathematics"
      ],
      "examples": [
        {
          "text": "13 is a happy number because 1² + 3² is 10, and 1² + 0² is 1.",
          "type": "example"
        }
      ],
      "glosses": [
        "Any number that eventually reaches 1 after some number of iterations of replacing each of its digits by the sum of that digit's squares."
      ],
      "links": [
        [
          "mathematics",
          "mathematics"
        ],
        [
          "iteration",
          "iteration"
        ],
        [
          "digit",
          "digit"
        ],
        [
          "sum",
          "sum"
        ],
        [
          "square",
          "square"
        ]
      ],
      "raw_glosses": [
        "(mathematics) Any number that eventually reaches 1 after some number of iterations of replacing each of its digits by the sum of that digit's squares."
      ],
      "topics": [
        "mathematics",
        "sciences"
      ]
    }
  ],
  "word": "happy number"
}