1211209999709 has 2 divisors, whose sum is σ = 1211209999710. Its totient is φ = 1211209999708.

The previous prime is 1211209999691. The next prime is 1211209999721. The reversal of 1211209999709 is 9079999021121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1208526448900 + 2683550809 = 1099330^2 + 51803^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211209999709 - 2⁴⁰ = 111698371933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211209999409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605604999854 + 605604999855.

It is an arithmetic number, because the mean of its divisors is an integer number (605604999855).

Almost surely, 2^{1211209999709} is an apocalyptic number.

It is an amenable number.

1211209999709 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211209999709 is an equidigital number, since it uses as much as digits as its factorization.

1211209999709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1653372, while the sum is 59.

The spelling of 1211209999709 in words is "one trillion, two hundred eleven billion, two hundred nine million, nine hundred ninety-nine thousand, seven hundred nine".