208855109 has 2 divisors, whose sum is σ = 208855110. Its totient is φ = 208855108.

The previous prime is 208855069. The next prime is 208855123. The reversal of 208855109 is 901558802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 136656100 + 72199009 = 11690^2 + 8497^2 .

It is a cyclic number.

It is not a de Polignac number, because 208855109 - 2¹⁶ = 208789573 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208855609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104427554 + 104427555.

It is an arithmetic number, because the mean of its divisors is an integer number (104427555).

Almost surely, 2^208855109 is an apocalyptic number.

It is an amenable number.

208855109 is a deficient number, since it is larger than the sum of its proper divisors (1).

208855109 is an equidigital number, since it uses as much as digits as its factorization.

208855109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28800, while the sum is 38.

The square root of 208855109 is about 14451.8202659734. The cubic root of 208855109 is about 593.3100449205.

The spelling of 208855109 in words is "two hundred eight million, eight hundred fifty-five thousand, one hundred nine".