diff --git a/commands/edit-number/prime.js b/commands/edit-number/prime.js
index 63ce46d3..cbb0b11c 100644
--- a/commands/edit-number/prime.js
+++ b/commands/edit-number/prime.js
@@ -26,8 +26,8 @@ module.exports = class PrimeCommand extends Command {
 
 	isPrime(number) {
 		if (number < 2) return false;
-		for (let i = 2; i < number; i++) {
-			if (number % i === 0) return false;
+		for (let i = 2, s = Math.sqrt(number); i <= s; i++) {
+			if (number % i === 0) return false; 
 		}
 		return true;
 	}
diff --git a/package.json b/package.json
index 947024e4..10288722 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
 	"name": "xiao",
-	"version": "127.2.0",
+	"version": "127.2.1",
 	"description": "Your personal server companion.",
 	"main": "Xiao.js",
 	"scripts": {