643085568 has 90 divisors (see below), whose sum is σ = 1917626634. Its totient is φ = 214354944.

The previous prime is 643085563. The next prime is 643085591. The reversal of 643085568 is 865580346.

643085568 is a `hidden beast` number, since 6 + 4 + 3 + 0 + 85 + 568 = 666.

It can be written as a sum of positive squares in only one way, i.e., 334450944 + 308634624 = 18288^2 + 17568^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643085561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 5230 + ... + 36242.

Almost surely, 2^643085568 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643085568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (958813317).

643085568 is an abundant number, since it is smaller than the sum of its proper divisors (1274541066).

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

643085568 is an equidigital number, since it uses as much as digits as its factorization.

643085568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31041 (or 31018 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 45.

The square root of 643085568 is about 25359.1318463389. The cubic root of 643085568 is about 863.1565843536.

The spelling of 643085568 in words is "six hundred forty-three million, eighty-five thousand, five hundred sixty-eight".