128555969 has 2 divisors, whose sum is σ = 128555970. Its totient is φ = 128555968.

The previous prime is 128555963. The next prime is 128555971. The reversal of 128555969 is 969555821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 123321025 + 5234944 = 11105^2 + 2288^2 .

It is a cyclic number.

It is not a de Polignac number, because 128555969 - 2⁴ = 128555953 is a prime.

It is a super-2 number, since 2×128555969² = 33053274331057922, which contains 22 as substring.

Together with 128555971, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (128555963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64277984 + 64277985.

It is an arithmetic number, because the mean of its divisors is an integer number (64277985).

Almost surely, 2^128555969 is an apocalyptic number.

It is an amenable number.

128555969 is a deficient number, since it is larger than the sum of its proper divisors (1).

128555969 is an equidigital number, since it uses as much as digits as its factorization.

128555969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 972000, while the sum is 50.

The square root of 128555969 is about 11338.2524667605. The cubic root of 128555969 is about 504.6970296564.

The spelling of 128555969 in words is "one hundred twenty-eight million, five hundred fifty-five thousand, nine hundred sixty-nine".