128638858650 has 24 divisors (see below), whose sum is σ = 319024369824. Its totient is φ = 34303695600.

The previous prime is 128638858639. The next prime is 128638858651. The reversal of 128638858650 is 56858836821.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (128638858651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 428796046 + ... + 428796345.

It is an arithmetic number, because the mean of its divisors is an integer number (13292682076).

Almost surely, 2^128638858650 is an apocalyptic number.

128638858650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

128638858650 is an abundant number, since it is smaller than the sum of its proper divisors (190385511174).

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

128638858650 is a wasteful number, since it uses less digits than its factorization.

128638858650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 857592406 (or 857592401 counting only the distinct ones).

The product of its (nonzero) digits is 22118400, while the sum is 60.

The spelling of 128638858650 in words is "one hundred twenty-eight billion, six hundred thirty-eight million, eight hundred fifty-eight thousand, six hundred fifty".