646355321 has 2 divisors, whose sum is σ = 646355322. Its totient is φ = 646355320.

The previous prime is 646355293. The next prime is 646355323. The reversal of 646355321 is 123553646.

646355321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 641355625 + 4999696 = 25325^2 + 2236^2 .

It is a cyclic number.

It is not a de Polignac number, because 646355321 - 2¹⁴ = 646338937 is a prime.

Together with 646355323, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_33613694 and since 646355321 and 33613694 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (646355323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323177660 + 323177661.

It is an arithmetic number, because the mean of its divisors is an integer number (323177661).

Almost surely, 2^646355321 is an apocalyptic number.

It is an amenable number.

646355321 is a deficient number, since it is larger than the sum of its proper divisors (1).

646355321 is an equidigital number, since it uses as much as digits as its factorization.

646355321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64800, while the sum is 35.

The square root of 646355321 is about 25423.5190522477. The cubic root of 646355321 is about 864.6170115590.

The spelling of 646355321 in words is "six hundred forty-six million, three hundred fifty-five thousand, three hundred twenty-one".