643336879 has 2 divisors, whose sum is σ = 643336880. Its totient is φ = 643336878.

The previous prime is 643336873. The next prime is 643336907. The reversal of 643336879 is 978633346.

643336879 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643336879 - 2⁵ = 643336847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643336873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321668439 + 321668440.

It is an arithmetic number, because the mean of its divisors is an integer number (321668440).

Almost surely, 2^643336879 is an apocalyptic number.

643336879 is a deficient number, since it is larger than the sum of its proper divisors (1).

643336879 is an equidigital number, since it uses as much as digits as its factorization.

643336879 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1959552, while the sum is 49.

The square root of 643336879 is about 25364.0864018399. The cubic root of 643336879 is about 863.2690071812.

The spelling of 643336879 in words is "six hundred forty-three million, three hundred thirty-six thousand, eight hundred seventy-nine".