643660800 has 396 divisors, whose sum is σ = 2337755880. Its totient is φ = 155975680.

The previous prime is 643660753. The next prime is 643660813. The reversal of 643660800 is 8066346.

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 22195186 + ... + 22195214.

Almost surely, 2^643660800 is an apocalyptic number.

643660800 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 643660800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1168877940).

643660800 is an abundant number, since it is smaller than the sum of its proper divisors (1694095080).

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

643660800 is a wasteful number, since it uses less digits than its factorization.

643660800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 56 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 643660800 is about 25370.4710244016. The cubic root of 643660800 is about 863.4138685805.

The spelling of 643660800 in words is "six hundred forty-three million, six hundred sixty thousand, eight hundred".