643336878 has 16 divisors (see below), whose sum is σ = 1287470160. Its totient is φ = 214312896.

The previous prime is 643336873. The next prime is 643336879. The reversal of 643336878 is 878633346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643336873) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22413 + ... + 42296.

It is an arithmetic number, because the mean of its divisors is an integer number (80466885).

Almost surely, 2^643336878 is an apocalyptic number.

643336878 is an abundant number, since it is smaller than the sum of its proper divisors (644133282).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643336878 is a wasteful number, since it uses less digits than its factorization.

643336878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66371.

The product of its digits is 1741824, while the sum is 48.

The square root of 643336878 is about 25364.0863821270. The cubic root of 643336878 is about 863.2690067339.

The spelling of 643336878 in words is "six hundred forty-three million, three hundred thirty-six thousand, eight hundred seventy-eight".