428221 has 2 divisors, whose sum is σ = 428222. Its totient is φ = 428220.

The previous prime is 428177. The next prime is 428227. The reversal of 428221 is 122824.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 264196 + 164025 = 514^2 + 405^2 .

It is a cyclic number.

It is not a de Polignac number, because 428221 - 2⁷ = 428093 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (428227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 214110 + 214111.

It is an arithmetic number, because the mean of its divisors is an integer number (214111).

2⁴²⁸²²¹ is an apocalyptic number.

It is an amenable number.

428221 is a deficient number, since it is larger than the sum of its proper divisors (1).

428221 is an equidigital number, since it uses as much as digits as its factorization.

428221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 256, while the sum is 19.

The square root of 428221 is about 654.3859717323. The cubic root of 428221 is about 75.3741892532.

The spelling of 428221 in words is "four hundred twenty-eight thousand, two hundred twenty-one".