1216312213 has 2 divisors, whose sum is σ = 1216312214. Its totient is φ = 1216312212.

The previous prime is 1216312159. The next prime is 1216312231. The reversal of 1216312213 is 3122136121.

It is a happy number.

Together with next prime (1216312231) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1084911844 + 131400369 = 32938^2 + 11463^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216312213 - 2¹³ = 1216304021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1216312613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608156106 + 608156107.

It is an arithmetic number, because the mean of its divisors is an integer number (608156107).

Almost surely, 2^1216312213 is an apocalyptic number.

It is an amenable number.

1216312213 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216312213 is an equidigital number, since it uses as much as digits as its factorization.

1216312213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 22.

The square root of 1216312213 is about 34875.6679219194. The cubic root of 1216312213 is about 1067.4520014178.

Adding to 1216312213 its reverse (3122136121), we get a palindrome (4338448334).

The spelling of 1216312213 in words is "one billion, two hundred sixteen million, three hundred twelve thousand, two hundred thirteen".