12782821 has 4 divisors (see below), whose sum is σ = 12790432. Its totient is φ = 12775212.

The previous prime is 12782807. The next prime is 12782831. The reversal of 12782821 is 12828721.

12782821 is digitally balanced in base 3, 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, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 12782821 - 2⁵ = 12782789 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 (12782831) 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 3 ways as a sum of consecutive naturals, for example, 51 + ... + 5056.

It is an arithmetic number, because the mean of its divisors is an integer number (3197608).

Almost surely, 2^12782821 is an apocalyptic number.

It is an amenable number.

12782821 is a deficient number, since it is larger than the sum of its proper divisors (7611).

12782821 is an equidigital number, since it uses as much as digits as its factorization.

12782821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7610.

The product of its digits is 3584, while the sum is 31.

The square root of 12782821 is about 3575.3071196752. The cubic root of 12782821 is about 233.8167228286.

The spelling of 12782821 in words is "twelve million, seven hundred eighty-two thousand, eight hundred twenty-one".