12561263361 has 6 divisors (see below), whose sum is σ = 18144047090. Its totient is φ = 8374175568.

The previous prime is 12561263359. The next prime is 12561263383. The reversal of 12561263361 is 16336216521.

12561263361 is a `hidden beast` number, since 1 + 2 + 5 + 6 + 12 + 633 + 6 + 1 = 666.

12561263361 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 12537056961 + 24206400 = 111969^2 + 4920^2 .

It is not a de Polignac number, because 12561263361 - 2¹ = 12561263359 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12561267361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 697847956 + ... + 697847973.

Almost surely, 2^12561263361 is an apocalyptic number.

It is an amenable number.

12561263361 is a deficient number, since it is larger than the sum of its proper divisors (5582783729).

12561263361 is a wasteful number, since it uses less digits than its factorization.

12561263361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1395695935 (or 1395695932 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

Adding to 12561263361 its reverse (16336216521), we get a palindrome (28897479882).

The spelling of 12561263361 in words is "twelve billion, five hundred sixty-one million, two hundred sixty-three thousand, three hundred sixty-one".