643605696 has 112 divisors (see below), whose sum is σ = 1991766400. Its totient is φ = 203233536.

The previous prime is 643605679. The next prime is 643605707. The reversal of 643605696 is 696506346.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23031 + ... + 42633.

Almost surely, 2^643605696 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 643605696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (995883200).

643605696 is an abundant number, since it is smaller than the sum of its proper divisors (1348160704).

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

643605696 is a wasteful number, since it uses less digits than its factorization.

643605696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19643 (or 19627 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 45.

The square root of 643605696 is about 25369.3850142253. The cubic root of 643605696 is about 863.3892288347.

The spelling of 643605696 in words is "six hundred forty-three million, six hundred five thousand, six hundred ninety-six".