216667609 has 2 divisors, whose sum is σ = 216667610. Its totient is φ = 216667608.

The previous prime is 216667559. The next prime is 216667651. The reversal of 216667609 is 906766612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212139225 + 4528384 = 14565^2 + 2128^2 .

It is a cyclic number.

It is not a de Polignac number, because 216667609 - 2⁹ = 216667097 is a prime.

It is not a weakly prime, because it can be changed into another prime (216667309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108333804 + 108333805.

It is an arithmetic number, because the mean of its divisors is an integer number (108333805).

Almost surely, 2^216667609 is an apocalyptic number.

It is an amenable number.

216667609 is a deficient number, since it is larger than the sum of its proper divisors (1).

216667609 is an equidigital number, since it uses as much as digits as its factorization.

216667609 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 43.

The square root of 216667609 is about 14719.6334533167. The cubic root of 216667609 is about 600.6175207104.

The spelling of 216667609 in words is "two hundred sixteen million, six hundred sixty-seven thousand, six hundred nine".