128689237 has 4 divisors (see below), whose sum is σ = 128976300. Its totient is φ = 128402176.

The previous prime is 128689229. The next prime is 128689241. The reversal of 128689237 is 732986821.

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 64144081 + 64545156 = 8009^2 + 8034^2 .

It is a cyclic number.

It is not a de Polignac number, because 128689237 - 2³ = 128689229 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 (128689217) 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, 142858 + ... + 143755.

It is an arithmetic number, because the mean of its divisors is an integer number (32244075).

Almost surely, 2^128689237 is an apocalyptic number.

It is an amenable number.

128689237 is a deficient number, since it is larger than the sum of its proper divisors (287063).

128689237 is an equidigital number, since it uses as much as digits as its factorization.

128689237 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287062.

The product of its digits is 290304, while the sum is 46.

The square root of 128689237 is about 11344.1278642300. The cubic root of 128689237 is about 504.8713680811.

The spelling of 128689237 in words is "one hundred twenty-eight million, six hundred eighty-nine thousand, two hundred thirty-seven".