643760128 has 136 divisors (see below), whose sum is σ = 1509937920. Its totient is φ = 271319040.

The previous prime is 643760111. The next prime is 643760129. The reversal of 643760128 is 821067346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643760129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13697001 + ... + 13697047.

Almost surely, 2^643760128 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 643760128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (754968960).

643760128 is an abundant number, since it is smaller than the sum of its proper divisors (866177792).

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

643760128 is an equidigital number, since it uses as much as digits as its factorization.

643760128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 79 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 643760128 is about 25372.4285002441. The cubic root of 643760128 is about 863.4582795299.

The spelling of 643760128 in words is "six hundred forty-three million, seven hundred sixty thousand, one hundred twenty-eight".