643523888 has 80 divisors (see below), whose sum is σ = 1453716480. Its totient is φ = 270286848.

The previous prime is 643523887. The next prime is 643523897. The reversal of 643523888 is 888325346.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (643523887) 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, 2273795 + ... + 2274077.

It is an arithmetic number, because the mean of its divisors is an integer number (18171456).

Almost surely, 2^643523888 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 643523888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (726858240).

643523888 is an abundant number, since it is smaller than the sum of its proper divisors (810192592).

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

643523888 is a wasteful number, since it uses less digits than its factorization.

643523888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 634 (or 628 counting only the distinct ones).

The product of its digits is 1105920, while the sum is 47.

The square root of 643523888 is about 25367.7726259126. The cubic root of 643523888 is about 863.3526458050.

The spelling of 643523888 in words is "six hundred forty-three million, five hundred twenty-three thousand, eight hundred eighty-eight".