643552880 has 80 divisors (see below), whose sum is σ = 1567024704. Its totient is φ = 245329920.

The previous prime is 643552879. The next prime is 643552883. The reversal of 643552880 is 88255346.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643552883) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 730040 + ... + 730920.

Almost surely, 2^643552880 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 643552880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (783512352).

643552880 is an abundant number, since it is smaller than the sum of its proper divisors (923471824).

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

643552880 is a wasteful number, since it uses less digits than its factorization.

643552880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1314 (or 1308 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 41.

The square root of 643552880 is about 25368.3440531699. The cubic root of 643552880 is about 863.3656108476.

The spelling of 643552880 in words is "six hundred forty-three million, five hundred fifty-two thousand, eight hundred eighty".