643403878 has 32 divisors (see below), whose sum is σ = 1123647840. Its totient is φ = 273715200.

The previous prime is 643403861. The next prime is 643403921. The reversal of 643403878 is 878304346.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 678 + ... + 35878.

It is an arithmetic number, because the mean of its divisors is an integer number (35113995).

Almost surely, 2^643403878 is an apocalyptic number.

643403878 is a deficient number, since it is larger than the sum of its proper divisors (480243962).

643403878 is a wasteful number, since it uses less digits than its factorization.

643403878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35272.

The product of its (nonzero) digits is 387072, while the sum is 43.

The square root of 643403878 is about 25365.4071128378. The cubic root of 643403878 is about 863.2989739344.

The spelling of 643403878 in words is "six hundred forty-three million, four hundred three thousand, eight hundred seventy-eight".