12666728065 has 8 divisors (see below), whose sum is σ = 15226790760. Its totient is φ = 10115571072.

The previous prime is 12666728059. The next prime is 12666728069. The reversal of 12666728065 is 56082766621.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 432598401 + 12234129664 = 20799^2 + 110608^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12666728065 - 2¹⁹ = 12666203777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12666728069) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2223294 + ... + 2228983.

It is an arithmetic number, because the mean of its divisors is an integer number (1903348845).

Almost surely, 2^12666728065 is an apocalyptic number.

It is an amenable number.

12666728065 is a deficient number, since it is larger than the sum of its proper divisors (2560062695).

12666728065 is an equidigital number, since it uses as much as digits as its factorization.

12666728065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4452851.

The product of its (nonzero) digits is 1451520, while the sum is 49.

The spelling of 12666728065 in words is "twelve billion, six hundred sixty-six million, seven hundred twenty-eight thousand, sixty-five".