diff --git a/app/lib/entity/membership.js b/app/lib/entity/membership.js
index fa015135b597d8c4c6e3f042c22967c1e51d9de1..b312451abf0ee483629c7e2da2b8d4f18d4f1c10 100644
--- a/app/lib/entity/membership.js
+++ b/app/lib/entity/membership.js
@@ -12,7 +12,7 @@ var Membership = function(json) {
     that[key] = json[key];
   });
 
-  this.blockNumber = this.number;
+  this.blockNumber = isNaN(this.number) ? this.number : parseInt(this.number);
   this.blockHash = this.fpr;
   this.version = "1";