216646609 has 2 divisors, whose sum is σ = 216646610. Its totient is φ = 216646608.

The previous prime is 216646603. The next prime is 216646649. The reversal of 216646609 is 906646612.

It is an a-pointer prime, because the next prime (216646649) can be obtained adding 216646609 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 123099025 + 93547584 = 11095^2 + 9672^2 .

It is a cyclic number.

It is not a de Polignac number, because 216646609 - 2³ = 216646601 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216646601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108323304 + 108323305.

It is an arithmetic number, because the mean of its divisors is an integer number (108323305).

Almost surely, 2^216646609 is an apocalyptic number.

It is an amenable number.

216646609 is a deficient number, since it is larger than the sum of its proper divisors (1).

216646609 is an equidigital number, since it uses as much as digits as its factorization.

216646609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 93312, while the sum is 40.

The square root of 216646609 is about 14718.9201030510. The cubic root of 216646609 is about 600.5981156018.

The spelling of 216646609 in words is "two hundred sixteen million, six hundred forty-six thousand, six hundred nine".