Emirp Calculator

The Emirp calculator is a free online tool used to check if a number is emirp.

Emirp Calculator

Eg, Is 11 a emirp number? Enter 11 into the input box and click Calculate button.

What is an emirp?

Just like its name, reverse the prime number to get a new number that is still a prime number. Then, this prime number is called an emirp.

For example, the prime number 13, reverse the order is 31. 31 is still a prime number, so 13 is an emirp.

A fun fact, if a prime number is an emirp, then reversing the prime is also an emirp. This fact can be easily seen from the above example.

Note that the reversed prime number is a new number, not the same as the original. For example, 101 is prime, but the reverse of 101 is still 101, so 101 is not an emirp. The same is true for one-digit prime numbers, so, 2, 3, 5 and 7 are not emirps.

First 100 emirps

13	17	31	37	71	73	79	97	107	113
149	157	167	179	199	311	337	347	359	389
701	709	733	739	743	751	761	769	907	937
941	953	967	971	983	991	1009	1021	1031	1033
1061	1069	1091	1097	1103	1109	1151	1153	1181	1193
1201	1213	1217	1223	1229	1231	1237	1249	1259	1279
1283	1301	1321	1381	1399	1409	1429	1439	1453	1471
1487	1499	1511	1523	1559	1583	1597	1601	1619	1657
1669	1723	1733	1741	1753	1789	1811	1831	1847	1867
1879	1901	1913	1933	1949	1979	3011	3019	3023	3049

How to use the emirp calculator

The procedure to use the emirp calculator is as follows:

1Enter a positive integer.
2Click calculate button to check whether the input integer is an emirp.
3Click the reset button to start a new verification.

Solved examples using the emirp calculator

Example 1: Is 59 an emirp number?

Enter 59 into the input box and click Calculate button, as shown in the figure, 59 is not an emirp.

Example 2: Is 137 an emirp number?

Enter 137 into the input box and click Calculate button, as shown in the figure, 137 is not an emirp.

Example 3: Is 1021 an emirp number?

Enter 1021 into the input box and click Calculate button, as shown in the figure, 1021 is an emirp.

Emirp Calculator