1213111243 has 2 divisors, whose sum is σ = 1213111244. Its totient is φ = 1213111242.

The previous prime is 1213111217. The next prime is 1213111247. The reversal of 1213111243 is 3421113121.

It is a strong prime.

It is an emirp because it is prime and its reverse (3421113121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1213111243 - 2²⁵ = 1179556811 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1213111243.

It is not a weakly prime, because it can be changed into another prime (1213111247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606555621 + 606555622.

It is an arithmetic number, because the mean of its divisors is an integer number (606555622).

Almost surely, 2^1213111243 is an apocalyptic number.

1213111243 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213111243 is an equidigital number, since it uses as much as digits as its factorization.

1213111243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 19.

The square root of 1213111243 is about 34829.7465250610. The cubic root of 1213111243 is about 1066.5147739554.

Adding to 1213111243 its reverse (3421113121), we get a palindrome (4634224364).

The spelling of 1213111243 in words is "one billion, two hundred thirteen million, one hundred eleven thousand, two hundred forty-three".