128788394641 has 9 divisors (see below), whose sum is σ = 129263489211. Its totient is φ = 128315043792.

The previous prime is 128788394627. The next prime is 128788394663. The reversal of 128788394641 is 146493887821.

The square root of 128788394641 is 358871.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 6780699025 + 122007695616 = 82345^2 + 349296^2 .

It is not a de Polignac number, because 128788394641 - 2⁹ = 128788394129 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128788394641.

It is not an unprimeable number, because it can be changed into a prime (128788394611) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 137447125 + ... + 137448061.

Almost surely, 2^128788394641 is an apocalyptic number.

128788394641 is the 358871-st square number.

128788394641 is the 179436-th centered octagonal number.

It is an amenable number.

128788394641 is a deficient number, since it is larger than the sum of its proper divisors (475094570).

128788394641 is an frugal number, since it uses more digits than its factorization.

128788394641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2640 (or 1320 counting only the distinct ones).

The product of its digits is 18579456, while the sum is 61.

The spelling of 128788394641 in words is "one hundred twenty-eight billion, seven hundred eighty-eight million, three hundred ninety-four thousand, six hundred forty-one".