128992709 has 2 divisors, whose sum is σ = 128992710. Its totient is φ = 128992708.

The previous prime is 128992681. The next prime is 128992711. The reversal of 128992709 is 907299821.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 126112900 + 2879809 = 11230^2 + 1697^2 .

It is a cyclic number.

It is not a de Polignac number, because 128992709 - 2²⁰ = 127944133 is a prime.

Together with 128992711, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128992309) 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, 64496354 + 64496355.

It is an arithmetic number, because the mean of its divisors is an integer number (64496355).

Almost surely, 2^128992709 is an apocalyptic number.

It is an amenable number.

128992709 is a deficient number, since it is larger than the sum of its proper divisors (1).

128992709 is an equidigital number, since it uses as much as digits as its factorization.

128992709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 128992709 is about 11357.4957186873. The cubic root of 128992709 is about 505.2679152191.

The spelling of 128992709 in words is "one hundred twenty-eight million, nine hundred ninety-two thousand, seven hundred nine".