128508005 has 4 divisors (see below), whose sum is σ = 154209612. Its totient is φ = 102806400.

The previous prime is 128507983. The next prime is 128508013. The reversal of 128508005 is 500805821.

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 39413284 + 89094721 = 6278^2 + 9439^2 .

It is not a de Polignac number, because 128508005 - 2²² = 124313701 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12850796 + ... + 12850805.

It is an arithmetic number, because the mean of its divisors is an integer number (38552403).

Almost surely, 2^128508005 is an apocalyptic number.

It is an amenable number.

128508005 is a deficient number, since it is larger than the sum of its proper divisors (25701607).

128508005 is an equidigital number, since it uses as much as digits as its factorization.

128508005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25701606.

The product of its (nonzero) digits is 3200, while the sum is 29.

The square root of 128508005 is about 11336.1371286695. The cubic root of 128508005 is about 504.6342546651.

The spelling of 128508005 in words is "one hundred twenty-eight million, five hundred eight thousand, five".