1211321203109 has 2 divisors, whose sum is σ = 1211321203110. Its totient is φ = 1211321203108.

The previous prime is 1211321203093. The next prime is 1211321203121. The reversal of 1211321203109 is 9013021231121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 673999950625 + 537321252484 = 820975^2 + 733022^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211321203109 - 2⁴ = 1211321203093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211321203009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605660601554 + 605660601555.

It is an arithmetic number, because the mean of its divisors is an integer number (605660601555).

Almost surely, 2^{1211321203109} is an apocalyptic number.

It is an amenable number.

1211321203109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211321203109 is an equidigital number, since it uses as much as digits as its factorization.

1211321203109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

The spelling of 1211321203109 in words is "one trillion, two hundred eleven billion, three hundred twenty-one million, two hundred three thousand, one hundred nine".