304221821 has 2 divisors, whose sum is σ = 304221822. Its totient is φ = 304221820.

The previous prime is 304221773. The next prime is 304221857. The reversal of 304221821 is 128122403.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 187279225 + 116942596 = 13685^2 + 10814^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-304221821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (304221221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 152110910 + 152110911.

It is an arithmetic number, because the mean of its divisors is an integer number (152110911).

Almost surely, 2^304221821 is an apocalyptic number.

It is an amenable number.

304221821 is a deficient number, since it is larger than the sum of its proper divisors (1).

304221821 is an equidigital number, since it uses as much as digits as its factorization.

304221821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 304221821 is about 17441.9557676311. The cubic root of 304221821 is about 672.5585847444.

The spelling of 304221821 in words is "three hundred four million, two hundred twenty-one thousand, eight hundred twenty-one".