12161726561 has 2 divisors, whose sum is σ = 12161726562. Its totient is φ = 12161726560.

The previous prime is 12161726539. The next prime is 12161726597. The reversal of 12161726561 is 16562716121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12050550625 + 111175936 = 109775^2 + 10544^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12161726561 is a prime.

It is not a weakly prime, because it can be changed into another prime (12161726861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6080863280 + 6080863281.

It is an arithmetic number, because the mean of its divisors is an integer number (6080863281).

Almost surely, 2^12161726561 is an apocalyptic number.

It is an amenable number.

12161726561 is a deficient number, since it is larger than the sum of its proper divisors (1).

12161726561 is an equidigital number, since it uses as much as digits as its factorization.

12161726561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 38.

The spelling of 12161726561 in words is "twelve billion, one hundred sixty-one million, seven hundred twenty-six thousand, five hundred sixty-one".