194555561 has 2 divisors, whose sum is σ = 194555562. Its totient is φ = 194555560.

The previous prime is 194555533. The next prime is 194555563. The reversal of 194555561 is 165555491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165611161 + 28944400 = 12869^2 + 5380^2 .

It is an emirp because it is prime and its reverse (165555491) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-194555561 is a prime.

It is a Sophie Germain prime.

Together with 194555563, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (194555563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97277780 + 97277781.

It is an arithmetic number, because the mean of its divisors is an integer number (97277781).

Almost surely, 2^194555561 is an apocalyptic number.

It is an amenable number.

194555561 is a deficient number, since it is larger than the sum of its proper divisors (1).

194555561 is an equidigital number, since it uses as much as digits as its factorization.

194555561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 135000, while the sum is 41.

The square root of 194555561 is about 13948.3174971034. The cubic root of 194555561 is about 579.4481085927.

The spelling of 194555561 in words is "one hundred ninety-four million, five hundred fifty-five thousand, five hundred sixty-one".