304220321 has 4 divisors (see below), whose sum is σ = 322115652. Its totient is φ = 286324992.

The previous prime is 304220309. The next prime is 304220341. The reversal of 304220321 is 123022403.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 123022403 = 7 ⋅17574629.

It can be written as a sum of positive squares in 2 ways, for example, as 170563600 + 133656721 = 13060^2 + 11561^2 .

It is a cyclic number.

It is not a de Polignac number, because 304220321 - 2¹⁸ = 303958177 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 17895313 = 304220321 / (3 + 0 + 4 + 2 + 2 + 0 + 3 + 2 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 304220321.

It is not an unprimeable number, because it can be changed into a prime (304220341) 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, 8947640 + ... + 8947673.

It is an arithmetic number, because the mean of its divisors is an integer number (80528913).

Almost surely, 2^304220321 is an apocalyptic number.

It is an amenable number.

304220321 is a deficient number, since it is larger than the sum of its proper divisors (17895331).

304220321 is a wasteful number, since it uses less digits than its factorization.

304220321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17895330.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 304220321 is about 17441.9127678131. The cubic root of 304220321 is about 672.5574793672.

Adding to 304220321 its reverse (123022403), we get a palindrome (427242724).

The spelling of 304220321 in words is "three hundred four million, two hundred twenty thousand, three hundred twenty-one".