128436839 has 4 divisors (see below), whose sum is σ = 128925456. Its totient is φ = 127948224.

The previous prime is 128436809. The next prime is 128436851. The reversal of 128436839 is 938634821.

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 128436839 - 2²⁰ = 127388263 is a prime.

It is a super-2 number, since 2×128436839² = 32992043224623842, which contains 22 as substring.

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 128436839.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128436809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 243914 + ... + 244439.

It is an arithmetic number, because the mean of its divisors is an integer number (32231364).

Almost surely, 2^128436839 is an apocalyptic number.

128436839 is a deficient number, since it is larger than the sum of its proper divisors (488617).

128436839 is an equidigital number, since it uses as much as digits as its factorization.

128436839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 488616.

The product of its digits is 248832, while the sum is 44.

The square root of 128436839 is about 11332.9977940526. The cubic root of 128436839 is about 504.5410842494.

The spelling of 128436839 in words is "one hundred twenty-eight million, four hundred thirty-six thousand, eight hundred thirty-nine".