diff --git a/project_euler/problem_058/sol1.py b/project_euler/problem_058/sol1.py
index d3b15157f..ed407edf7 100644
--- a/project_euler/problem_058/sol1.py
+++ b/project_euler/problem_058/sol1.py
@@ -33,11 +33,12 @@ So we check individually each one of these before incrementing our
 count of current primes.
 
 """
+from math import isqrt
 
 
-def isprime(d: int) -> int:
+def isprime(number: int) -> int:
     """
-    returns whether the given digit is prime or not
+    returns whether the given number is prime or not
     >>> isprime(1)
     0
     >>> isprime(17)
@@ -45,14 +46,15 @@ def isprime(d: int) -> int:
     >>> isprime(10000)
     0
     """
-    if d == 1:
+    if number == 1:
         return 0
 
-    i = 2
-    while i * i <= d:
-        if d % i == 0:
+    if number % 2 == 0 and number > 2:
+        return 0
+
+    for i in range(3, isqrt(number) + 1, 2):
+        if number % i == 0:
             return 0
-        i = i + 1
     return 1