128705305 has 8 divisors (see below), whose sum is σ = 155813832. Its totient is φ = 102052608.

The previous prime is 128705261. The next prime is 128705329. The reversal of 128705305 is 503507821.

It can be written as a sum of positive squares in 4 ways, for example, as 2996361 + 125708944 = 1731^2 + 11212^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128705305 - 2⁷ = 128705177 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 113334 + ... + 114463.

It is an arithmetic number, because the mean of its divisors is an integer number (19476729).

Almost surely, 2^128705305 is an apocalyptic number.

It is an amenable number.

128705305 is a deficient number, since it is larger than the sum of its proper divisors (27108527).

128705305 is a wasteful number, since it uses less digits than its factorization.

128705305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227915.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 128705305 is about 11344.8360499392. The cubic root of 128705305 is about 504.8923797724.

The spelling of 128705305 in words is "one hundred twenty-eight million, seven hundred five thousand, three hundred five".