12666861 has 12 divisors (see below), whose sum is σ = 18974592. Its totient is φ = 8444412.

The previous prime is 12666851. The next prime is 12666877. The reversal of 12666861 is 16866621.

12666861 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12666861 - 2¹³ = 12658669 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12666821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25821 + ... + 26306.

It is an arithmetic number, because the mean of its divisors is an integer number (1581216).

Almost surely, 2^12666861 is an apocalyptic number.

It is an amenable number.

12666861 is a deficient number, since it is larger than the sum of its proper divisors (6307731).

12666861 is an frugal number, since it uses more digits than its factorization.

12666861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52142 (or 52130 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 12666861 is about 3559.0533853821. The cubic root of 12666861 is about 233.1075473473.

The spelling of 12666861 in words is "twelve million, six hundred sixty-six thousand, eight hundred sixty-one".