30978209 has 2 divisors, whose sum is σ = 30978210. Its totient is φ = 30978208.

The previous prime is 30978203. The next prime is 30978229. The reversal of 30978209 is 90287903.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21827584 + 9150625 = 4672^2 + 3025^2 .

It is a cyclic number.

It is not a de Polignac number, because 30978209 - 2⁴ = 30978193 is a prime.

It is not a weakly prime, because it can be changed into another prime (30978203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15489104 + 15489105.

It is an arithmetic number, because the mean of its divisors is an integer number (15489105).

Almost surely, 2^30978209 is an apocalyptic number.

It is an amenable number.

30978209 is a deficient number, since it is larger than the sum of its proper divisors (1).

30978209 is an equidigital number, since it uses as much as digits as its factorization.

30978209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 30978209 is about 5565.8071292491. The cubic root of 30978209 is about 314.0644417213.

The spelling of 30978209 in words is "thirty million, nine hundred seventy-eight thousand, two hundred nine".