306221 has 4 divisors (see below), whose sum is σ = 324252. Its totient is φ = 288192.

The previous prime is 306209. The next prime is 306239. The reversal of 306221 is 122603.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122603 = 13 ⋅9431.

It can be written as a sum of positive squares in 2 ways, for example, as 264196 + 42025 = 514^2 + 205^2 .

It is a cyclic number.

It is not a de Polignac number, because 306221 - 2⁶ = 306157 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 306196 and 306205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (306121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8990 + ... + 9023.

It is an arithmetic number, because the mean of its divisors is an integer number (81063).

2³⁰⁶²²¹ is an apocalyptic number.

It is an amenable number.

306221 is a deficient number, since it is larger than the sum of its proper divisors (18031).

306221 is a wasteful number, since it uses less digits than its factorization.

306221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18030.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 306221 is about 553.3723881800. The cubic root of 306221 is about 67.4028598140.

Adding to 306221 its reverse (122603), we get a palindrome (428824).

The spelling of 306221 in words is "three hundred six thousand, two hundred twenty-one".