1211209999849 has 2 divisors, whose sum is σ = 1211209999850. Its totient is φ = 1211209999848.

The previous prime is 1211209999847. The next prime is 1211209999903. The reversal of 1211209999849 is 9489999021121.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1195250225625 + 15959774224 = 1093275^2 + 126332^2 .

It is an emirp because it is prime and its reverse (9489999021121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1211209999849 - 2¹ = 1211209999847 is a prime.

Together with 1211209999847, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1211209999841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605604999924 + 605604999925.

It is an arithmetic number, because the mean of its divisors is an integer number (605604999925).

Almost surely, 2^{1211209999849} is an apocalyptic number.

It is an amenable number.

1211209999849 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211209999849 is an equidigital number, since it uses as much as digits as its factorization.

1211209999849 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7558272, while the sum is 64.

The spelling of 1211209999849 in words is "one trillion, two hundred eleven billion, two hundred nine million, nine hundred ninety-nine thousand, eight hundred forty-nine".