12855821 has 4 divisors (see below), whose sum is σ = 14024544. Its totient is φ = 11687100.

The previous prime is 12855809. The next prime is 12855823.

It is a happy number.

12855821 is nontrivially palindromic in base 10.

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 a de Polignac number, because none of the positive numbers 2^k-12855821 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 (12855823) 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, 584345 + ... + 584366.

It is an arithmetic number, because the mean of its divisors is an integer number (3506136).

Almost surely, 2^12855821 is an apocalyptic number.

12855821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12855821 is a deficient number, since it is larger than the sum of its proper divisors (1168723).

12855821 is a wasteful number, since it uses less digits than its factorization.

12855821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1168722.

The product of its digits is 6400, while the sum is 32.

The square root of 12855821 is about 3585.5014990933. The cubic root of 12855821 is about 234.2609709252.

The spelling of 12855821 in words is "twelve million, eight hundred fifty-five thousand, eight hundred twenty-one".