643878558 has 48 divisors (see below), whose sum is σ = 1449302400. Its totient is φ = 214246296.

The previous prime is 643878523. The next prime is 643878569. The reversal of 643878558 is 855878346.

643878558 is a `hidden beast` number, since 6 + 4 + 3 + 87 + 8 + 558 = 666.

643878558 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 459543 + ... + 460941.

It is an arithmetic number, because the mean of its divisors is an integer number (30193800).

Almost surely, 2^643878558 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643878558, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (724651200).

643878558 is an abundant number, since it is smaller than the sum of its proper divisors (805423842).

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

643878558 is a wasteful number, since it uses less digits than its factorization.

643878558 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2363 (or 2351 counting only the distinct ones).

The product of its digits is 6451200, while the sum is 54.

The square root of 643878558 is about 25374.7622254870. The cubic root of 643878558 is about 863.5112252828.

The spelling of 643878558 in words is "six hundred forty-three million, eight hundred seventy-eight thousand, five hundred fifty-eight".