1211340129661 has 2 divisors, whose sum is σ = 1211340129662. Its totient is φ = 1211340129660.

The previous prime is 1211340129599. The next prime is 1211340129667. The reversal of 1211340129661 is 1669210431121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1081870416900 + 129469712761 = 1040130^2 + 359819^2 .

It is an emirp because it is prime and its reverse (1669210431121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1211340129661 - 2¹⁹ = 1211339605373 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211340129661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211340129667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605670064830 + 605670064831.

It is an arithmetic number, because the mean of its divisors is an integer number (605670064831).

Almost surely, 2^{1211340129661} is an apocalyptic number.

It is an amenable number.

1211340129661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211340129661 is an equidigital number, since it uses as much as digits as its factorization.

1211340129661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 37.

The spelling of 1211340129661 in words is "one trillion, two hundred eleven billion, three hundred forty million, one hundred twenty-nine thousand, six hundred sixty-one".