128694388985 has 4 divisors (see below), whose sum is σ = 154433266788. Its totient is φ = 102955511184.

The previous prime is 128694388969. The next prime is 128694389003. The reversal of 128694388985 is 589883496821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 49310199481 + 79384189504 = 222059^2 + 281752^2 .

It is a cyclic number.

It is not a de Polignac number, because 128694388985 - 2⁴ = 128694388969 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12869438894 + ... + 12869438903.

It is an arithmetic number, because the mean of its divisors is an integer number (38608316697).

Almost surely, 2^128694388985 is an apocalyptic number.

It is an amenable number.

128694388985 is a deficient number, since it is larger than the sum of its proper divisors (25738877803).

128694388985 is an equidigital number, since it uses as much as digits as its factorization.

128694388985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25738877802.

The product of its digits is 238878720, while the sum is 71.

The spelling of 128694388985 in words is "one hundred twenty-eight billion, six hundred ninety-four million, three hundred eighty-eight thousand, nine hundred eighty-five".