12728557 has 4 divisors (see below), whose sum is σ = 12783420. Its totient is φ = 12673696.

The previous prime is 12728549. The next prime is 12728561. The reversal of 12728557 is 75582721.

12728557 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5470921 + 7257636 = 2339^2 + 2694^2 .

It is a cyclic number.

It is not a de Polignac number, because 12728557 - 2³ = 12728549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12728567) 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, 27082 + ... + 27547.

It is an arithmetic number, because the mean of its divisors is an integer number (3195855).

Almost surely, 2^12728557 is an apocalyptic number.

It is an amenable number.

12728557 is a deficient number, since it is larger than the sum of its proper divisors (54863).

12728557 is an equidigital number, since it uses as much as digits as its factorization.

12728557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54862.

The product of its digits is 39200, while the sum is 37.

The square root of 12728557 is about 3567.7103301698. The cubic root of 12728557 is about 233.4853972499.

The spelling of 12728557 in words is "twelve million, seven hundred twenty-eight thousand, five hundred fifty-seven".