12661569869 has 4 divisors (see below), whose sum is σ = 13635536796. Its totient is φ = 11687602944.

The previous prime is 12661569863. The next prime is 12661569881. The reversal of 12661569869 is 96896516621.

12661569869 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7926340900 + 4735228969 = 89030^2 + 68813^2 .

It is a cyclic number.

It is not a de Polignac number, because 12661569869 - 2²⁴ = 12644792653 is a prime.

It is a super-2 number, since 2×12661569869² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12661569863) 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 3 ways as a sum of consecutive naturals, for example, 486983444 + ... + 486983469.

It is an arithmetic number, because the mean of its divisors is an integer number (3408884199).

Almost surely, 2^12661569869 is an apocalyptic number.

It is an amenable number.

12661569869 is a deficient number, since it is larger than the sum of its proper divisors (973966927).

12661569869 is an equidigital number, since it uses as much as digits as its factorization.

12661569869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 973966926.

The product of its digits is 8398080, while the sum is 59.

The spelling of 12661569869 in words is "twelve billion, six hundred sixty-one million, five hundred sixty-nine thousand, eight hundred sixty-nine".