128589661 has 2 divisors, whose sum is σ = 128589662. Its totient is φ = 128589660.

The previous prime is 128589631. The next prime is 128589679. The reversal of 128589661 is 166985821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125328025 + 3261636 = 11195^2 + 1806^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128589661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128589631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64294830 + 64294831.

It is an arithmetic number, because the mean of its divisors is an integer number (64294831).

Almost surely, 2^128589661 is an apocalyptic number.

It is an amenable number.

128589661 is a deficient number, since it is larger than the sum of its proper divisors (1).

128589661 is an equidigital number, since it uses as much as digits as its factorization.

128589661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 207360, while the sum is 46.

The square root of 128589661 is about 11339.7381363063. The cubic root of 128589661 is about 504.7411162054.

The spelling of 128589661 in words is "one hundred twenty-eight million, five hundred eighty-nine thousand, six hundred sixty-one".