128395657 has 4 divisors (see below), whose sum is σ = 138272260. Its totient is φ = 118519056.

The previous prime is 128395639. The next prime is 128395691. The reversal of 128395657 is 756593821.

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 18481401 + 109914256 = 4299^2 + 10484^2 .

It is a cyclic number.

It is not a de Polignac number, because 128395657 - 2¹¹ = 128393609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128335657) 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, 4938282 + ... + 4938307.

It is an arithmetic number, because the mean of its divisors is an integer number (34568065).

Almost surely, 2^128395657 is an apocalyptic number.

It is an amenable number.

128395657 is a deficient number, since it is larger than the sum of its proper divisors (9876603).

128395657 is an equidigital number, since it uses as much as digits as its factorization.

128395657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9876602.

The product of its digits is 453600, while the sum is 46.

The square root of 128395657 is about 11331.1807416527. The cubic root of 128395657 is about 504.4871531181.

It can be divided in two parts, 12839 and 5657, that added together give a square (18496 = 136²).

The spelling of 128395657 in words is "one hundred twenty-eight million, three hundred ninety-five thousand, six hundred fifty-seven".