12728649 has 4 divisors (see below), whose sum is σ = 16971536. Its totient is φ = 8485764.

The previous prime is 12728609. The next prime is 12728657. The reversal of 12728649 is 94682721.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 12728649 - 2¹² = 12724553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12728609) 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, 2121439 + ... + 2121444.

It is an arithmetic number, because the mean of its divisors is an integer number (4242884).

Almost surely, 2^12728649 is an apocalyptic number.

It is an amenable number.

12728649 is a deficient number, since it is larger than the sum of its proper divisors (4242887).

12728649 is an equidigital number, since it uses as much as digits as its factorization.

12728649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4242886.

The product of its digits is 48384, while the sum is 39.

The square root of 12728649 is about 3567.7232235699. The cubic root of 12728649 is about 233.4859597804.

The spelling of 12728649 in words is "twelve million, seven hundred twenty-eight thousand, six hundred forty-nine".