128012405 has 12 divisors (see below), whose sum is σ = 162127692. Its totient is φ = 97018560.

The previous prime is 128012393. The next prime is 128012407. The reversal of 128012405 is 504210821.

It can be written as a sum of positive squares in 2 ways, for example, as 87740689 + 40271716 = 9367^2 + 6346^2 .

It is not a de Polignac number, because 128012405 - 2⁸ = 128012149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128012407) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 33656 + ... + 37265.

It is an arithmetic number, because the mean of its divisors is an integer number (13510641).

Almost surely, 2^128012405 is an apocalyptic number.

It is an amenable number.

128012405 is a deficient number, since it is larger than the sum of its proper divisors (34115287).

128012405 is an equidigital number, since it uses as much as digits as its factorization.

128012405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70964 (or 70945 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 128012405 is about 11314.2567144289. The cubic root of 128012405 is about 503.9846999744.

The spelling of 128012405 in words is "one hundred twenty-eight million, twelve thousand, four hundred five".