128425609 has 4 divisors (see below), whose sum is σ = 138304516. Its totient is φ = 118546704.

The previous prime is 128425607. The next prime is 128425663. The reversal of 128425609 is 906524821.

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 30969225 + 97456384 = 5565^2 + 9872^2 .

It is a cyclic number.

It is not a de Polignac number, because 128425609 - 2¹ = 128425607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128425603) 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, 4939434 + ... + 4939459.

It is an arithmetic number, because the mean of its divisors is an integer number (34576129).

Almost surely, 2^128425609 is an apocalyptic number.

It is an amenable number.

128425609 is a deficient number, since it is larger than the sum of its proper divisors (9878907).

128425609 is an equidigital number, since it uses as much as digits as its factorization.

128425609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9878906.

The product of its (nonzero) digits is 34560, while the sum is 37.

The square root of 128425609 is about 11332.5023273768. The cubic root of 128425609 is about 504.5263788072.

The spelling of 128425609 in words is "one hundred twenty-eight million, four hundred twenty-five thousand, six hundred nine".