208309788809 has 2 divisors, whose sum is σ = 208309788810. Its totient is φ = 208309788808.

The previous prime is 208309788787. The next prime is 208309788829. The reversal of 208309788809 is 908887903802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 174473290000 + 33836498809 = 417700^2 + 183947^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-208309788809 is a prime.

It is a super-2 number, since 2×208309788809² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (208309788829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104154894404 + 104154894405.

It is an arithmetic number, because the mean of its divisors is an integer number (104154894405).

Almost surely, 2^208309788809 is an apocalyptic number.

It is an amenable number.

208309788809 is a deficient number, since it is larger than the sum of its proper divisors (1).

208309788809 is an equidigital number, since it uses as much as digits as its factorization.

208309788809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13934592, while the sum is 62.

The spelling of 208309788809 in words is "two hundred eight billion, three hundred nine million, seven hundred eighty-eight thousand, eight hundred nine".