128508913939 has 4 divisors (see below), whose sum is σ = 146867330224. Its totient is φ = 110150497656.

The previous prime is 128508913937. The next prime is 128508913987. The reversal of 128508913939 is 939319805821.

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

It is a cyclic number.

It is not a de Polignac number, because 128508913939 - 2¹ = 128508913937 is a prime.

It is a super-3 number, since 3×128508913939³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128508913937) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9179208132 + ... + 9179208145.

It is an arithmetic number, because the mean of its divisors is an integer number (36716832556).

Almost surely, 2^128508913939 is an apocalyptic number.

128508913939 is a deficient number, since it is larger than the sum of its proper divisors (18358416285).

128508913939 is an equidigital number, since it uses as much as digits as its factorization.

128508913939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18358416284.

The product of its (nonzero) digits is 4199040, while the sum is 58.

The spelling of 128508913939 in words is "one hundred twenty-eight billion, five hundred eight million, nine hundred thirteen thousand, nine hundred thirty-nine".