1211231213 has 2 divisors, whose sum is σ = 1211231214. Its totient is φ = 1211231212.

The previous prime is 1211231123. The next prime is 1211231233. The reversal of 1211231213 is 3121321121.

Together with previous prime (1211231123) 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., 669877924 + 541353289 = 25882^2 + 23267^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211231213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1211231191 and 1211231200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211231233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605615606 + 605615607.

It is an arithmetic number, because the mean of its divisors is an integer number (605615607).

Almost surely, 2^1211231213 is an apocalyptic number.

It is an amenable number.

1211231213 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211231213 is an equidigital number, since it uses as much as digits as its factorization.

1211231213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72, while the sum is 17.

The square root of 1211231213 is about 34802.7472047826. The cubic root of 1211231213 is about 1065.9635421615.

Adding to 1211231213 its reverse (3121321121), we get a palindrome (4332552334).

The spelling of 1211231213 in words is "one billion, two hundred eleven million, two hundred thirty-one thousand, two hundred thirteen".