208194269561 has 2 divisors, whose sum is σ = 208194269562. Its totient is φ = 208194269560.

The previous prime is 208194269531. The next prime is 208194269567. The reversal of 208194269561 is 165962491802.

208194269561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 180357349225 + 27836920336 = 424685^2 + 166844^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-208194269561 is a prime.

It is a super-2 number, since 2×208194269561² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (208194269567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104097134780 + 104097134781.

It is an arithmetic number, because the mean of its divisors is an integer number (104097134781).

Almost surely, 2^208194269561 is an apocalyptic number.

It is an amenable number.

208194269561 is a deficient number, since it is larger than the sum of its proper divisors (1).

208194269561 is an equidigital number, since it uses as much as digits as its factorization.

208194269561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1866240, while the sum is 53.

The spelling of 208194269561 in words is "two hundred eight billion, one hundred ninety-four million, two hundred sixty-nine thousand, five hundred sixty-one".