643405360 has 80 divisors (see below), whose sum is σ = 1695828960. Its totient is φ = 225054720.

The previous prime is 643405331. The next prime is 643405363. The reversal of 643405360 is 63504346.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (643405363) by changing a digit.

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, 3480 + ... + 36040.

It is an arithmetic number, because the mean of its divisors is an integer number (21197862).

Almost surely, 2^643405360 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 643405360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (847914480).

643405360 is an abundant number, since it is smaller than the sum of its proper divisors (1052423600).

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

643405360 is a wasteful number, since it uses less digits than its factorization.

643405360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32606 (or 32600 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 31.

The square root of 643405360 is about 25365.4363258352. The cubic root of 643405360 is about 863.2996367675.

The spelling of 643405360 in words is "six hundred forty-three million, four hundred five thousand, three hundred sixty".