128991794389 has 2 divisors, whose sum is σ = 128991794390. Its totient is φ = 128991794388.

The previous prime is 128991794377. The next prime is 128991794453. The reversal of 128991794389 is 983497199821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 90867279364 + 38124515025 = 301442^2 + 195255^2 .

It is a cyclic number.

It is not a de Polignac number, because 128991794389 - 2¹¹ = 128991792341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128991794339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64495897194 + 64495897195.

It is an arithmetic number, because the mean of its divisors is an integer number (64495897195).

Almost surely, 2^128991794389 is an apocalyptic number.

It is an amenable number.

128991794389 is a deficient number, since it is larger than the sum of its proper divisors (1).

128991794389 is an equidigital number, since it uses as much as digits as its factorization.

128991794389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 70543872, while the sum is 70.

The spelling of 128991794389 in words is "one hundred twenty-eight billion, nine hundred ninety-one million, seven hundred ninety-four thousand, three hundred eighty-nine".