643338337 has 2 divisors, whose sum is σ = 643338338. Its totient is φ = 643338336.

The previous prime is 643338299. The next prime is 643338379. The reversal of 643338337 is 733833346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 433638976 + 209699361 = 20824^2 + 14481^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643338337 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643338337.

It is not a weakly prime, because it can be changed into another prime (643338637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321669168 + 321669169.

It is an arithmetic number, because the mean of its divisors is an integer number (321669169).

Almost surely, 2^643338337 is an apocalyptic number.

It is an amenable number.

643338337 is a deficient number, since it is larger than the sum of its proper divisors (1).

643338337 is an equidigital number, since it uses as much as digits as its factorization.

643338337 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 40.

The square root of 643338337 is about 25364.1151432491. The cubic root of 643338337 is about 863.2696593254.

The spelling of 643338337 in words is "six hundred forty-three million, three hundred thirty-eight thousand, three hundred thirty-seven".