12661605 has 24 divisors (see below), whose sum is σ = 23942880. Its totient is φ = 6138720.

The previous prime is 12661591. The next prime is 12661613. The reversal of 12661605 is 50616621.

It is a happy number.

It is not a de Polignac number, because 12661605 - 2⁴ = 12661589 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12295 + ... + 13284.

It is an arithmetic number, because the mean of its divisors is an integer number (997620).

Almost surely, 2^12661605 is an apocalyptic number.

12661605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

12661605 is a deficient number, since it is larger than the sum of its proper divisors (11281275).

12661605 is a wasteful number, since it uses less digits than its factorization.

12661605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25601 (or 25598 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 12661605 is about 3558.3149101787. The cubic root of 12661605 is about 233.0753009270.

The spelling of 12661605 in words is "twelve million, six hundred sixty-one thousand, six hundred five".