1、NSNumber转NSString

                NSNumber *number = @(YES);
if(number && [number isKindOfClass:[NSNumber class]])
{
//若考虑为空或NSString类型的情况,该方法兼容性比较好
NSString *String = [NSString StringWithFormat:@"%@",number];
//或者 该方法一定要判断类型不然可能闪退
// NSString *String = number.description;
}

NSString字符串如何转为NSNumber

2、NSString 转 NSNumber

                NSString *str = @"327691";
NSNumber *number = nil;
if(str)
{
number = @(0);
}
else if([str isKindOfClass:[NSString class]])
{
// 字符串先转成long long类型,再转对象
number = @([str longLongValue]);
}