12606556561 has 2 divisors, whose sum is σ = 12606556562. Its totient is φ = 12606556560.

The previous prime is 12606556513. The next prime is 12606556579. The reversal of 12606556561 is 16565560621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11827867536 + 778689025 = 108756^2 + 27905^2 .

It is an emirp because it is prime and its reverse (16565560621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12606556561 - 2⁹ = 12606556049 is a prime.

It is not a weakly prime, because it can be changed into another prime (12606556961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6303278280 + 6303278281.

It is an arithmetic number, because the mean of its divisors is an integer number (6303278281).

Almost surely, 2^12606556561 is an apocalyptic number.

It is an amenable number.

12606556561 is a deficient number, since it is larger than the sum of its proper divisors (1).

12606556561 is an equidigital number, since it uses as much as digits as its factorization.

12606556561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324000, while the sum is 43.

The spelling of 12606556561 in words is "twelve billion, six hundred six million, five hundred fifty-six thousand, five hundred sixty-one".