643505311 has 2 divisors, whose sum is σ = 643505312. Its totient is φ = 643505310.

The previous prime is 643505279. The next prime is 643505351. The reversal of 643505311 is 113505346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643505311 - 2⁵ = 643505279 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643505311.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643505351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321752655 + 321752656.

It is an arithmetic number, because the mean of its divisors is an integer number (321752656).

Almost surely, 2^643505311 is an apocalyptic number.

643505311 is a deficient number, since it is larger than the sum of its proper divisors (1).

643505311 is an equidigital number, since it uses as much as digits as its factorization.

643505311 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 643505311 is about 25367.4064697202. The cubic root of 643505311 is about 863.3443380810.

The spelling of 643505311 in words is "six hundred forty-three million, five hundred five thousand, three hundred eleven".