643338379 has 2 divisors, whose sum is σ = 643338380. Its totient is φ = 643338378.

The previous prime is 643338337. The next prime is 643338403. The reversal of 643338379 is 973833346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643338379 - 2⁷ = 643338251 is a prime.

It is not a weakly prime, because it can be changed into another prime (643338779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321669189 + 321669190.

It is an arithmetic number, because the mean of its divisors is an integer number (321669190).

Almost surely, 2^643338379 is an apocalyptic number.

643338379 is a deficient number, since it is larger than the sum of its proper divisors (1).

643338379 is an equidigital number, since it uses as much as digits as its factorization.

643338379 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 46.

The square root of 643338379 is about 25364.1159711905. The cubic root of 643338379 is about 863.2696781114.

The spelling of 643338379 in words is "six hundred forty-three million, three hundred thirty-eight thousand, three hundred seventy-nine".