1213121311 has 2 divisors, whose sum is σ = 1213121312. Its totient is φ = 1213121310.

The previous prime is 1213121297. The next prime is 1213121323. The reversal of 1213121311 is 1131213121.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1213121311 - 2⁵ = 1213121279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213121341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606560655 + 606560656.

It is an arithmetic number, because the mean of its divisors is an integer number (606560656).

Almost surely, 2^1213121311 is an apocalyptic number.

1213121311 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213121311 is an equidigital number, since it uses as much as digits as its factorization.

1213121311 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36, while the sum is 16.

The square root of 1213121311 is about 34829.8910563901. The cubic root of 1213121311 is about 1066.5177243968.

Adding to 1213121311 its reverse (1131213121), we get a palindrome (2344334432).

It can be divided in two parts, 1 and 213121311, that added together give a palindrome (213121312).

The spelling of 1213121311 in words is "one billion, two hundred thirteen million, one hundred twenty-one thousand, three hundred eleven".