12856921 has 8 divisors (see below), whose sum is σ = 16029504. Its totient is φ = 10018320.

The previous prime is 12856891. The next prime is 12856933. The reversal of 12856921 is 12965821.

12856921 = 209² + 210² + ... + 362².

12856921 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12856921 - 2¹³ = 12848729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12856021) 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 7 ways as a sum of consecutive naturals, for example, 83410 + ... + 83563.

It is an arithmetic number, because the mean of its divisors is an integer number (2003688).

Almost surely, 2^12856921 is an apocalyptic number.

12856921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12856921 is a deficient number, since it is larger than the sum of its proper divisors (3172583).

12856921 is a wasteful number, since it uses less digits than its factorization.

12856921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166991.

The product of its digits is 8640, while the sum is 34.

The square root of 12856921 is about 3585.6548913692. The cubic root of 12856921 is about 234.2676521974.

Subtracting 12856921 from its reverse (12965821), we obtain a square (108900 = 330²).

The spelling of 12856921 in words is "twelve million, eight hundred fifty-six thousand, nine hundred twenty-one".