855221 has 2 divisors, whose sum is σ = 855222. Its totient is φ = 855220.

The previous prime is 855203. The next prime is 855229. The reversal of 855221 is 122558.

855221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 784996 + 70225 = 886^2 + 265^2 .

It is a cyclic number.

It is not a de Polignac number, because 855221 - 2¹⁴ = 838837 is a prime.

It is a Chen prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (855229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 427610 + 427611.

It is an arithmetic number, because the mean of its divisors is an integer number (427611).

2⁸⁵⁵²²¹ is an apocalyptic number.

It is an amenable number.

855221 is a deficient number, since it is larger than the sum of its proper divisors (1).

855221 is an equidigital number, since it uses as much as digits as its factorization.

855221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 800, while the sum is 23.

The square root of 855221 is about 924.7815958376. The cubic root of 855221 is about 94.9203764961.

Adding to 855221 its reverse (122558), we get a palindrome (977779).

The spelling of 855221 in words is "eight hundred fifty-five thousand, two hundred twenty-one".