643360321 has 2 divisors, whose sum is σ = 643360322. Its totient is φ = 643360320.

The previous prime is 643360309. The next prime is 643360327. The reversal of 643360321 is 123063346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 372297025 + 271063296 = 19295^2 + 16464^2 .

It is a cyclic number.

It is not a de Polignac number, because 643360321 - 2¹¹ = 643358273 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643360321.

It is not a weakly prime, because it can be changed into another prime (643360327) 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, 321680160 + 321680161.

It is an arithmetic number, because the mean of its divisors is an integer number (321680161).

Almost surely, 2^643360321 is an apocalyptic number.

It is an amenable number.

643360321 is a deficient number, since it is larger than the sum of its proper divisors (1).

643360321 is an equidigital number, since it uses as much as digits as its factorization.

643360321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 28.

The square root of 643360321 is about 25364.5485077105. The cubic root of 643360321 is about 863.2794923598.

The spelling of 643360321 in words is "six hundred forty-three million, three hundred sixty thousand, three hundred twenty-one".