208109197 has 2 divisors, whose sum is σ = 208109198. Its totient is φ = 208109196.

The previous prime is 208109183. The next prime is 208109219. The reversal of 208109197 is 791901802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 130210921 + 77898276 = 11411^2 + 8826^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-208109197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208109177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104054598 + 104054599.

It is an arithmetic number, because the mean of its divisors is an integer number (104054599).

Almost surely, 2^208109197 is an apocalyptic number.

It is an amenable number.

208109197 is a deficient number, since it is larger than the sum of its proper divisors (1).

208109197 is an equidigital number, since it uses as much as digits as its factorization.

208109197 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 208109197 is about 14425.9903299566. The cubic root of 208109197 is about 592.6028800563.

It can be divided in two parts, 20810919 and 7, that added together give a triangular number (20810926 = T₆₄₅₁).

The spelling of 208109197 in words is "two hundred eight million, one hundred nine thousand, one hundred ninety-seven".