30128209 has 2 divisors, whose sum is σ = 30128210. Its totient is φ = 30128208.

The previous prime is 30128201. The next prime is 30128239. The reversal of 30128209 is 90282103.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27248400 + 2879809 = 5220^2 + 1697^2 .

It is an emirp because it is prime and its reverse (90282103) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30128209 - 2³ = 30128201 is a prime.

It is not a weakly prime, because it can be changed into another prime (30128201) 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, 15064104 + 15064105.

It is an arithmetic number, because the mean of its divisors is an integer number (15064105).

Almost surely, 2^30128209 is an apocalyptic number.

It is an amenable number.

30128209 is a deficient number, since it is larger than the sum of its proper divisors (1).

30128209 is an equidigital number, since it uses as much as digits as its factorization.

30128209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 30128209 is about 5488.9169241299. The cubic root of 30128209 is about 311.1652606096.

The spelling of 30128209 in words is "thirty million, one hundred twenty-eight thousand, two hundred nine".