643303217 has 2 divisors, whose sum is σ = 643303218. Its totient is φ = 643303216.

The previous prime is 643303207. The next prime is 643303223. The reversal of 643303217 is 712303346.

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., 562590961 + 80712256 = 23719^2 + 8984^2 .

It is a cyclic number.

It is not a de Polignac number, because 643303217 - 2¹⁶ = 643237681 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643303217.

It is not a weakly prime, because it can be changed into another prime (643303207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321651608 + 321651609.

It is an arithmetic number, because the mean of its divisors is an integer number (321651609).

Almost surely, 2^643303217 is an apocalyptic number.

It is an amenable number.

643303217 is a deficient number, since it is larger than the sum of its proper divisors (1).

643303217 is an equidigital number, since it uses as much as digits as its factorization.

643303217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 29.

The square root of 643303217 is about 25363.4228171199. The cubic root of 643303217 is about 863.2539503376.

The spelling of 643303217 in words is "six hundred forty-three million, three hundred three thousand, two hundred seventeen".