208920209 has 2 divisors, whose sum is σ = 208920210. Its totient is φ = 208920208.

The previous prime is 208920203. The next prime is 208920251. The reversal of 208920209 is 902029802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 110355025 + 98565184 = 10505^2 + 9928^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-208920209 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (208920203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104460104 + 104460105.

It is an arithmetic number, because the mean of its divisors is an integer number (104460105).

Almost surely, 2^208920209 is an apocalyptic number.

It is an amenable number.

208920209 is a deficient number, since it is larger than the sum of its proper divisors (1).

208920209 is an equidigital number, since it uses as much as digits as its factorization.

208920209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 208920209 is about 14454.0724019219. The cubic root of 208920209 is about 593.3716833002.

The spelling of 208920209 in words is "two hundred eight million, nine hundred twenty thousand, two hundred nine".