12566866521 has 48 divisors (see below), whose sum is σ = 19201641984. Its totient is φ = 7296960000.

The previous prime is 12566866519. The next prime is 12566866567.

12566866521 is nontrivially palindromic in base 10.

12566866521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12566866521 - 2¹ = 12566866519 is a prime.

It is a super-2 number, since 2×12566866521² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12566866511) 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 47 ways as a sum of consecutive naturals, for example, 1131025 + ... + 1142081.

It is an arithmetic number, because the mean of its divisors is an integer number (400034208).

Almost surely, 2^12566866521 is an apocalyptic number.

12566866521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12566866521 is a deficient number, since it is larger than the sum of its proper divisors (6634775463).

12566866521 is a wasteful number, since it uses less digits than its factorization.

12566866521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11214 (or 11203 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 48.

The spelling of 12566866521 in words is "twelve billion, five hundred sixty-six million, eight hundred sixty-six thousand, five hundred twenty-one".