195755821 has 2 divisors, whose sum is σ = 195755822. Its totient is φ = 195755820.

The previous prime is 195755779. The next prime is 195755827. The reversal of 195755821 is 128557591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 195720100 + 35721 = 13990^2 + 189^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-195755821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (195755827) 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, 97877910 + 97877911.

It is an arithmetic number, because the mean of its divisors is an integer number (97877911).

Almost surely, 2^195755821 is an apocalyptic number.

It is an amenable number.

195755821 is a deficient number, since it is larger than the sum of its proper divisors (1).

195755821 is an equidigital number, since it uses as much as digits as its factorization.

195755821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 126000, while the sum is 43.

The square root of 195755821 is about 13991.2766036556. The cubic root of 195755821 is about 580.6372514325.

The spelling of 195755821 in words is "one hundred ninety-five million, seven hundred fifty-five thousand, eight hundred twenty-one".