820430321 has 2 divisors, whose sum is σ = 820430322. Its totient is φ = 820430320.

The previous prime is 820430269. The next prime is 820430327. The reversal of 820430321 is 123034028.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 486820096 + 333610225 = 22064^2 + 18265^2 .

It is a cyclic number.

It is not a de Polignac number, because 820430321 - 2⁶ = 820430257 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (820430327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410215160 + 410215161.

It is an arithmetic number, because the mean of its divisors is an integer number (410215161).

Almost surely, 2^820430321 is an apocalyptic number.

It is an amenable number.

820430321 is a deficient number, since it is larger than the sum of its proper divisors (1).

820430321 is an equidigital number, since it uses as much as digits as its factorization.

820430321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 820430321 is about 28643.1548716268. The cubic root of 820430321 is about 936.1538638534.

Adding to 820430321 its reverse (123034028), we get a palindrome (943464349).

The spelling of 820430321 in words is "eight hundred twenty million, four hundred thirty thousand, three hundred twenty-one".