643930560 has 756 divisors, whose sum is σ = 2893225608. Its totient is φ = 135862272.

The previous prime is 643930531. The next prime is 643930561. The reversal of 643930560 is 65039346.

643930560 is a `hidden beast` number, since 6 + 4 + 3 + 93 + 0 + 560 = 666.

It is a tau number, because it is divible by the number of its divisors (756).

It is a super-2 number, since 2×643930560² = 829293132203827200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643930561) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 49533114 + ... + 49533126.

It is an arithmetic number, because the mean of its divisors is an integer number (3827018).

Almost surely, 2^643930560 is an apocalyptic number.

643930560 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643930560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1446612804).

643930560 is an abundant number, since it is smaller than the sum of its proper divisors (2249295048).

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

643930560 is a wasteful number, since it uses less digits than its factorization.

643930560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72 (or 30 counting only the distinct ones).

The product of its (nonzero) digits is 58320, while the sum is 36.

The square root of 643930560 is about 25375.7868843510. The cubic root of 643930560 is about 863.5344714376.

The spelling of 643930560 in words is "six hundred forty-three million, nine hundred thirty thousand, five hundred sixty".