12638666 has 4 divisors (see below), whose sum is σ = 18958002. Its totient is φ = 6319332.

The previous prime is 12638663. The next prime is 12638671. The reversal of 12638666 is 66683621.

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

It can be written as a sum of positive squares in only one way, i.e., 11417641 + 1221025 = 3379^2 + 1105^2 .

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 as a sum of consecutive naturals, namely, 3159665 + ... + 3159668.

Almost surely, 2^12638666 is an apocalyptic number.

12638666 is a deficient number, since it is larger than the sum of its proper divisors (6319336).

12638666 is an equidigital number, since it uses as much as digits as its factorization.

12638666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6319335.

The product of its digits is 62208, while the sum is 38.

The square root of 12638666 is about 3555.0901535685. The cubic root of 12638666 is about 232.9344618486.

The spelling of 12638666 in words is "twelve million, six hundred thirty-eight thousand, six hundred sixty-six".