12666402779 has 4 divisors (see below), whose sum is σ = 12669055776. Its totient is φ = 12663749784.

The previous prime is 12666402751. The next prime is 12666402901. The reversal of 12666402779 is 97720466621.

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

It is a cyclic number.

It is not a de Polignac number, because 12666402779 - 2²⁴ = 12649625563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12666402709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1319324 + ... + 1328889.

It is an arithmetic number, because the mean of its divisors is an integer number (3167263944).

Almost surely, 2^12666402779 is an apocalyptic number.

12666402779 is a deficient number, since it is larger than the sum of its proper divisors (2652997).

12666402779 is an equidigital number, since it uses as much as digits as its factorization.

12666402779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2652996.

The product of its (nonzero) digits is 1524096, while the sum is 50.

The spelling of 12666402779 in words is "twelve billion, six hundred sixty-six million, four hundred two thousand, seven hundred seventy-nine".