217030409 has 2 divisors, whose sum is σ = 217030410. Its totient is φ = 217030408.

The previous prime is 217030357. The next prime is 217030433. The reversal of 217030409 is 904030712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212343184 + 4687225 = 14572^2 + 2165^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217030409 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (217030439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108515204 + 108515205.

It is an arithmetic number, because the mean of its divisors is an integer number (108515205).

Almost surely, 2^217030409 is an apocalyptic number.

It is an amenable number.

217030409 is a deficient number, since it is larger than the sum of its proper divisors (1).

217030409 is an equidigital number, since it uses as much as digits as its factorization.

217030409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 217030409 is about 14731.9519752136. The cubic root of 217030409 is about 600.9525692933.

The spelling of 217030409 in words is "two hundred seventeen million, thirty thousand, four hundred nine".