218102009 has 2 divisors, whose sum is σ = 218102010. Its totient is φ = 218102008.

The previous prime is 218101999. The next prime is 218102021. The reversal of 218102009 is 900201812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 112423609 + 105678400 = 10603^2 + 10280^2 .

It is a cyclic number.

It is not a de Polignac number, because 218102009 - 2⁸ = 218101753 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (218102029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109051004 + 109051005.

It is an arithmetic number, because the mean of its divisors is an integer number (109051005).

Almost surely, 2^218102009 is an apocalyptic number.

It is an amenable number.

218102009 is a deficient number, since it is larger than the sum of its proper divisors (1).

218102009 is an equidigital number, since it uses as much as digits as its factorization.

218102009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 218102009 is about 14768.2771168474. The cubic root of 218102009 is about 601.9400250402.

The spelling of 218102009 in words is "two hundred eighteen million, one hundred two thousand, nine".