195643561 has 2 divisors, whose sum is σ = 195643562. Its totient is φ = 195643560.

The previous prime is 195643537. The next prime is 195643619. The reversal of 195643561 is 165346591.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138791961 + 56851600 = 11781^2 + 7540^2 .

It is a cyclic number.

It is not a de Polignac number, because 195643561 - 2⁵ = 195643529 is a prime.

It is not a weakly prime, because it can be changed into another prime (195643501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97821780 + 97821781.

It is an arithmetic number, because the mean of its divisors is an integer number (97821781).

Almost surely, 2^195643561 is an apocalyptic number.

It is an amenable number.

195643561 is a deficient number, since it is larger than the sum of its proper divisors (1).

195643561 is an equidigital number, since it uses as much as digits as its factorization.

195643561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 97200, while the sum is 40.

The square root of 195643561 is about 13987.2642428747. The cubic root of 195643561 is about 580.5262376169.

The spelling of 195643561 in words is "one hundred ninety-five million, six hundred forty-three thousand, five hundred sixty-one".