128605 has 12 divisors (see below), whose sum is σ = 165780. Its totient is φ = 95744.

The previous prime is 128603. The next prime is 128621. The reversal of 128605 is 506821.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 441 + 128164 = 21^2 + 358^2 .

It is not a de Polignac number, because 128605 - 2¹ = 128603 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128603) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1401 + ... + 1489.

It is an arithmetic number, because the mean of its divisors is an integer number (13815).

2¹²⁸⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

128605 is a deficient number, since it is larger than the sum of its proper divisors (37175).

128605 is an equidigital number, since it uses as much as digits as its factorization.

128605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 128605 is about 358.6153928654. The cubic root of 128605 is about 50.4761184994.

The spelling of 128605 in words is "one hundred twenty-eight thousand, six hundred five".