12855221 has 2 divisors, whose sum is σ = 12855222. Its totient is φ = 12855220.

The previous prime is 12855217. The next prime is 12855233. The reversal of 12855221 is 12255821.

12855221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7214596 + 5640625 = 2686^2 + 2375^2 .

It is an emirp because it is prime and its reverse (12255821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12855221 - 2² = 12855217 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12855211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6427610 + 6427611.

It is an arithmetic number, because the mean of its divisors is an integer number (6427611).

Almost surely, 2^12855221 is an apocalyptic number.

It is an amenable number.

12855221 is a deficient number, since it is larger than the sum of its proper divisors (1).

12855221 is an equidigital number, since it uses as much as digits as its factorization.

12855221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1600, while the sum is 26.

The square root of 12855221 is about 3585.4178278131. The cubic root of 12855221 is about 234.2573264342.

The spelling of 12855221 in words is "twelve million, eight hundred fifty-five thousand, two hundred twenty-one".