509221 has 2 divisors, whose sum is σ = 509222. Its totient is φ = 509220.

The previous prime is 509203. The next prime is 509227. The reversal of 509221 is 122905.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 264196 + 245025 = 514^2 + 495^2 .

It is a cyclic number.

It is not a de Polignac number, because 509221 - 2⁹ = 508709 is a prime.

It is equal to p₄₂₂₂₉ and since 509221 and 42229 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (509227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 254610 + 254611.

It is an arithmetic number, because the mean of its divisors is an integer number (254611).

2⁵⁰⁹²²¹ is an apocalyptic number.

It is an amenable number.

509221 is a deficient number, since it is larger than the sum of its proper divisors (1).

509221 is an equidigital number, since it uses as much as digits as its factorization.

509221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 509221 is about 713.5972253309. The cubic root of 509221 is about 79.8549977548.

The spelling of 509221 in words is "five hundred nine thousand, two hundred twenty-one".