12812921 has 4 divisors (see below), whose sum is σ = 13977744. Its totient is φ = 11648100.

The previous prime is 12812893. The next prime is 12812963. The reversal of 12812921 is 12921821.

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-12812921 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12812981) 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, 582395 + ... + 582416.

It is an arithmetic number, because the mean of its divisors is an integer number (3494436).

Almost surely, 2^12812921 is an apocalyptic number.

12812921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12812921 is a deficient number, since it is larger than the sum of its proper divisors (1164823).

12812921 is a wasteful number, since it uses less digits than its factorization.

12812921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1164822.

The product of its digits is 576, while the sum is 26.

The square root of 12812921 is about 3579.5140731669. The cubic root of 12812921 is about 234.0001034894. Note that the first 3 decimals are identical.

Subtracting 12812921 from its reverse (12921821), we obtain a square (108900 = 330²).

The spelling of 12812921 in words is "twelve million, eight hundred twelve thousand, nine hundred twenty-one".