intent.putExtra("EXTRA_NUMBER", numberAsAString);

final Intent intent = new Intent(this, myActivity2.class);
intent.putExtra("phone_number",((EditText)findViewById(R.id.edttxt_input)).getText().toString());
startActivity(intent);

String phoneNumber = getIntent().getStringExtra("phone_number");
String uri = "tel:" + phoneNumber;
Intent intent = new Intent(Intent.ACTION_CALL);
intent.setData(Uri.parse(uri));
startActivity(intent);