1216111313 has 2 divisors, whose sum is σ = 1216111314. Its totient is φ = 1216111312.

The previous prime is 1216111297. The next prime is 1216111327. The reversal of 1216111313 is 3131116121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1169092864 + 47018449 = 34192^2 + 6857^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216111313 - 2⁴ = 1216111297 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1216111333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608055656 + 608055657.

It is an arithmetic number, because the mean of its divisors is an integer number (608055657).

Almost surely, 2^1216111313 is an apocalyptic number.

It is an amenable number.

1216111313 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216111313 is an equidigital number, since it uses as much as digits as its factorization.

1216111313 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108, while the sum is 20.

The square root of 1216111313 is about 34872.7875714001. The cubic root of 1216111313 is about 1067.3932273320.

Adding to 1216111313 its reverse (3131116121), we get a palindrome (4347227434).

The spelling of 1216111313 in words is "one billion, two hundred sixteen million, one hundred eleven thousand, three hundred thirteen".