128393861 has 2 divisors, whose sum is σ = 128393862. Its totient is φ = 128393860.

The previous prime is 128393857. The next prime is 128393869. The reversal of 128393861 is 168393821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 100620961 + 27772900 = 10031^2 + 5270^2 .

It is a cyclic number.

It is not a de Polignac number, because 128393861 - 2² = 128393857 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128393869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64196930 + 64196931.

It is an arithmetic number, because the mean of its divisors is an integer number (64196931).

Almost surely, 2^128393861 is an apocalyptic number.

It is an amenable number.

128393861 is a deficient number, since it is larger than the sum of its proper divisors (1).

128393861 is an equidigital number, since it uses as much as digits as its factorization.

128393861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 62208, while the sum is 41.

The square root of 128393861 is about 11331.1014910290. The cubic root of 128393861 is about 504.4848008497.

The spelling of 128393861 in words is "one hundred twenty-eight million, three hundred ninety-three thousand, eight hundred sixty-one".