643970560 has 80 divisors (see below), whose sum is σ = 1611298656. Its totient is φ = 246366208.

The previous prime is 643970543. The next prime is 643970563. The reversal of 643970560 is 65079346.

643970560 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

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

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643970563) 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, 53412 + ... + 64348.

Almost surely, 2^643970560 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 643970560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (805649328).

643970560 is an abundant number, since it is smaller than the sum of its proper divisors (967328096).

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

643970560 is a wasteful number, since it uses less digits than its factorization.

643970560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10983 (or 10967 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 40.

The square root of 643970560 is about 25376.5750250108. The cubic root of 643970560 is about 863.5523515558.

The spelling of 643970560 in words is "six hundred forty-three million, nine hundred seventy thousand, five hundred sixty".