Add method that queries the mirror node to get the actual num field

src/EntityIdHelper.js

@@ -90,7 +90,7 @@ export function constructor(props, realmOrNull, numOrNull) {
         throw new Error("invalid entity ID");
     }
 
-    // If the first parameter is a nubmer then we need to conver the
+    // If the first parameter is a number then we need to convert the
     // first, second, and third parameters into numbers. Otherwise,
     // we should look at the fields `shard`, `realm`, and `num` on
     // `props`

src/account/AccountId.js

@@ -27,6 +27,7 @@ import CACHE from "../Cache.js";
 import EvmAddress from "../EvmAddress.js";
 import * as hex from ".././encoding/hex.js";
 import { isLongZeroAddress } from "../util.js";
+import axios from "axios";
 
 /**
  * @typedef {import("../client/Client.js").default<*, *>} Client
@@ -172,6 +173,34 @@ export default class AccountId {
         return this.evmAddress;
     }
 
+    /**
+     * @description Gets the actual `num` field of the `AccountId` from the Mirror Node.
+     * Should be used after generating `AccountId.fromEvmAddress()` because it sets the `num` field to `0`
+     * automatically since there is no connection between the `num` and the `evmAddress`
+     * @param {Client} client
+     * @returns {Promise<AccountId>}
+     */
+    async populateAccountNum(client) {
+        if (this.evmAddress === null) {
+            throw new Error("field `evmAddress` should not be null");
+        }
+        const mirrorUrl = client.mirrorNetwork[0].slice(
+            0,
+            client.mirrorNetwork[0].indexOf(":")
+        );
+
+        /* eslint-disable */
+        const url = `https://${mirrorUrl}/api/v1/accounts/${this.evmAddress.toString()}`;
+        const mirrorAccountId = (await axios.get(url)).data.account;
+
+        this.num = Long.fromString(
+            mirrorAccountId.slice(mirrorAccountId.lastIndexOf(".") + 1)
+        );
+        /* eslint-enable */
+
+        return this;
+    }
+
     /**
      * @deprecated - Use `validateChecksum` instead
      * @param {Client} client
@@ -226,7 +255,15 @@ export default class AccountId {
      * @returns {string}
      */
     toSolidityAddress() {
-        return entity_id.toSolidityAddress([this.shard, this.realm, this.num]);
+        if (this.evmAddress != null) {
+            return this.evmAddress.toString();
+        } else {
+            return entity_id.toSolidityAddress([
+                this.shard,
+                this.realm,
+                this.num,
+            ]);
+        }
     }
 
     //TODO remove the comments after we get to HIP-631

src/contract/ContractId.js

@@ -26,6 +26,7 @@ import * as hex from "../encoding/hex.js";
 import { arrayEqual } from "../array.js";
 import Long from "long";
 import { isLongZeroAddress } from "../util.js";
+import axios from "axios";
 
 /**
  * @typedef {import("../client/Client.js").default<*, *>} Client
@@ -117,6 +118,36 @@ export default class ContractId extends Key {
         return this._checksum;
     }
 
+    /**
+     * @description Gets the actual `num` field of the `ContractId` from the Mirror Node.
+     * Should be used after generating `ContractId.fromEvmAddress()` because it sets the `num` field to `0`
+     * automatically since there is no connection between the `num` and the `evmAddress`
+     * @param {Client} client
+     * @returns {Promise<ContractId>}
+     */
+    async populateAccountNum(client) {
+        if (this.evmAddress === null) {
+            throw new Error("field `evmAddress` should not be null");
+        }
+        const mirrorUrl = client.mirrorNetwork[0].slice(
+            0,
+            client.mirrorNetwork[0].indexOf(":")
+        );
+
+        /* eslint-disable */
+        const url = `https://${mirrorUrl}/api/v1/contracts/${hex.encode(
+            this.evmAddress
+        )}`;
+        const mirrorAccountId = (await axios.get(url)).data.contract_id;
+
+        this.num = Long.fromString(
+            mirrorAccountId.slice(mirrorAccountId.lastIndexOf(".") + 1)
+        );
+        /* eslint-enable */
+
+        return this;
+    }
+
     /**
      * @deprecated - Use `validateChecksum` instead
      * @param {Client} client