12800737447661 has 2 divisors, whose sum is σ = 12800737447662. Its totient is φ = 12800737447660.

The previous prime is 12800737447651. The next prime is 12800737447711. The reversal of 12800737447661 is 16674473700821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7326798721636 + 5473938726025 = 2706806^2 + 2339645^2 .

It is a cyclic number.

It is not a de Polignac number, because 12800737447661 - 2¹⁸ = 12800737185517 is a prime.

It is a super-3 number, since 3×12800737447661³ (a number of 40 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 12800737447597 and 12800737447606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12800737447651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6400368723830 + 6400368723831.

It is an arithmetic number, because the mean of its divisors is an integer number (6400368723831).

Almost surely, 2^{12800737447661} is an apocalyptic number.

It is an amenable number.

12800737447661 is a deficient number, since it is larger than the sum of its proper divisors (1).

12800737447661 is an equidigital number, since it uses as much as digits as its factorization.

12800737447661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9483264, while the sum is 56.

The spelling of 12800737447661 in words is "twelve trillion, eight hundred billion, seven hundred thirty-seven million, four hundred forty-seven thousand, six hundred sixty-one".