12728467857821 has 4 divisors (see below), whose sum is σ = 12729073102944. Its totient is φ = 12727862612700.

The previous prime is 12728467857769. The next prime is 12728467857857. The reversal of 12728467857821 is 12875876482721.

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 a cyclic number.

It is not a de Polignac number, because 12728467857821 - 2³⁸ = 12453589950877 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 (12728467857421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 302591015 + ... + 302633076.

It is an arithmetic number, because the mean of its divisors is an integer number (3182268275736).

Almost surely, 2^{12728467857821} is an apocalyptic number.

It is an amenable number.

12728467857821 is a deficient number, since it is larger than the sum of its proper divisors (605245123).

12728467857821 is an equidigital number, since it uses as much as digits as its factorization.

12728467857821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 605245122.

The product of its digits is 168591360, while the sum is 68.

The spelling of 12728467857821 in words is "twelve trillion, seven hundred twenty-eight billion, four hundred sixty-seven million, eight hundred fifty-seven thousand, eight hundred twenty-one".