128651009 has 2 divisors, whose sum is σ = 128651010. Its totient is φ = 128651008.

The previous prime is 128650993. The next prime is 128651011. The reversal of 128651009 is 900156821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 126000625 + 2650384 = 11225^2 + 1628^2 .

It is a cyclic number.

It is not a de Polignac number, because 128651009 - 2⁴ = 128650993 is a prime.

Together with 128651011, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_7305890 and since 128651009 and 7305890 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (128651069) 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, 64325504 + 64325505.

It is an arithmetic number, because the mean of its divisors is an integer number (64325505).

Almost surely, 2^128651009 is an apocalyptic number.

It is an amenable number.

128651009 is a deficient number, since it is larger than the sum of its proper divisors (1).

128651009 is an equidigital number, since it uses as much as digits as its factorization.

128651009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 128651009 is about 11342.4428144911. The cubic root of 128651009 is about 504.8213713228.

The spelling of 128651009 in words is "one hundred twenty-eight million, six hundred fifty-one thousand, nine".