diff --git a/slither/printers/guidance/echidna.py b/slither/printers/guidance/echidna.py
index e06f5ac2f..26f3221c3 100644
--- a/slither/printers/guidance/echidna.py
+++ b/slither/printers/guidance/echidna.py
@@ -130,7 +130,10 @@ def json_serializable(cls):
 
 @json_serializable
 class ConstantValue(NamedTuple):
-    value: Union[str, int, bool]
+    # Here value should be  Union[str, int, bool]
+    # But the json lib in Echidna does not handle large integer in json
+    # So we convert everything to string
+    value: str
     type: str
 
 
@@ -142,17 +145,17 @@ def _extract_constants_from_irs(irs: List[Operation],
         if isinstance(ir, Binary):
             for r in ir.read:
                 if isinstance(r, Constant):
-                    all_cst_used_in_binary[BinaryType.str(ir.type)].append(ConstantValue(r.value, str(r.type)))
+                    all_cst_used_in_binary[BinaryType.str(ir.type)].append(ConstantValue(str(r.value), str(r.type)))
         if isinstance(ir, TypeConversion):
             if isinstance(ir.variable, Constant):
-                all_cst_used.append(ConstantValue(ir.variable.value, str(ir.type)))
+                all_cst_used.append(ConstantValue(str(ir.variable.value), str(ir.type)))
                 continue
         for r in ir.read:
             # Do not report struct_name in a.struct_name
             if isinstance(ir, Member):
                 continue
             if isinstance(r, Constant):
-                all_cst_used.append(ConstantValue(r.value, str(r.type)))
+                all_cst_used.append(ConstantValue(str(r.value), str(r.type)))
             if isinstance(r, StateVariable):
                 if r.node_initialization:
                     if r.node_initialization.irs:
diff --git a/slither/slithir/variables/constant.py b/slither/slithir/variables/constant.py
index f77fe1774..1bee7e3bc 100644
--- a/slither/slithir/variables/constant.py
+++ b/slither/slithir/variables/constant.py
@@ -1,3 +1,5 @@
+from decimal import Decimal
+
 from .variable import SlithIRVariable
 from slither.core.solidity_types.elementary_type import ElementaryType, Int, Uint
 from slither.utils.arithmetic import convert_subdenomination
@@ -23,12 +25,12 @@ class Constant(SlithIRVariable):
                 else:
                     if 'e' in val:
                         base, expo = val.split('e')
-                        self._val = int(float(base)* (10 ** int(expo)))
+                        self._val = int(Decimal(base) * (10 ** int(expo)))
                     elif 'E' in val:
                         base, expo = val.split('E')
-                        self._val = int(float(base) * (10 ** int(expo)))
+                        self._val = int(Decimal(base) * (10 ** int(expo)))
                     else:
-                        self._val = int(float(val))
+                        self._val = int(Decimal(val))
             elif type.type == 'bool':
                 self._val = (val == 'true') | (val == 'True')
             else:
@@ -36,7 +38,7 @@ class Constant(SlithIRVariable):
         else:
             if val.isdigit():
                 self._type = ElementaryType('uint256')
-                self._val = int(val)
+                self._val = int(Decimal(val))
             else:
                 self._type = ElementaryType('string')
                 self._val = val
diff --git a/slither/utils/arithmetic.py b/slither/utils/arithmetic.py
index 241eca28a..0612b0a26 100644
--- a/slither/utils/arithmetic.py
+++ b/slither/utils/arithmetic.py
@@ -1,3 +1,5 @@
+from decimal import Decimal
+
 from slither.exceptions import SlitherException
 
 
@@ -5,9 +7,9 @@ def convert_subdenomination(value, sub):
 
     # to allow 0.1 ether conversion
     if value[0:2] == "0x":
-        value = float(int(value, 16))
+        value = Decimal(int(value, 16))
     else:
-        value = float(value)
+        value = Decimal(value)
     if sub == 'wei':
         return int(value)
     if sub == 'szabo':