12638665 has 12 divisors (see below), whose sum is σ = 16423884. Its totient is φ = 9332544.

The previous prime is 12638663. The next prime is 12638671. The reversal of 12638665 is 56683621.

It can be written as a sum of positive squares in 6 ways, for example, as 3924361 + 8714304 = 1981^2 + 2952^2 .

It is not a de Polignac number, because 12638665 - 2¹ = 12638663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12638663) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 6634 + ... + 8323.

It is an arithmetic number, because the mean of its divisors is an integer number (1368657).

Almost surely, 2^12638665 is an apocalyptic number.

It is an amenable number.

12638665 is a deficient number, since it is larger than the sum of its proper divisors (3785219).

12638665 is a wasteful number, since it uses less digits than its factorization.

12638665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14988 (or 14975 counting only the distinct ones).

The product of its digits is 51840, while the sum is 37.

The square root of 12638665 is about 3555.0900129251. The cubic root of 12638665 is about 232.9344557052.

The spelling of 12638665 in words is "twelve million, six hundred thirty-eight thousand, six hundred sixty-five".