208161091 has 2 divisors, whose sum is σ = 208161092. Its totient is φ = 208161090.

The previous prime is 208161089. The next prime is 208161103. The reversal of 208161091 is 190161802.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 208161091 - 2¹ = 208161089 is a prime.

Together with 208161089, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (208161011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104080545 + 104080546.

It is an arithmetic number, because the mean of its divisors is an integer number (104080546).

Almost surely, 2^208161091 is an apocalyptic number.

208161091 is a deficient number, since it is larger than the sum of its proper divisors (1).

208161091 is an equidigital number, since it uses as much as digits as its factorization.

208161091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 208161091 is about 14427.7888465281. The cubic root of 208161091 is about 592.6521330102.

The spelling of 208161091 in words is "two hundred eight million, one hundred sixty-one thousand, ninety-one".