12398505799661 has 2 divisors, whose sum is σ = 12398505799662. Its totient is φ = 12398505799660.

The previous prime is 12398505799651. The next prime is 12398505799711. The reversal of 12398505799661 is 16699750589321.

12398505799661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12197067304900 + 201438494761 = 3492430^2 + 448819^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12398505799661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12398505799651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6199252899830 + 6199252899831.

It is an arithmetic number, because the mean of its divisors is an integer number (6199252899831).

Almost surely, 2^{12398505799661} is an apocalyptic number.

It is an amenable number.

12398505799661 is a deficient number, since it is larger than the sum of its proper divisors (1).

12398505799661 is an equidigital number, since it uses as much as digits as its factorization.

12398505799661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 220449600, while the sum is 71.

The spelling of 12398505799661 in words is "twelve trillion, three hundred ninety-eight billion, five hundred five million, seven hundred ninety-nine thousand, six hundred sixty-one".