195821089 has 2 divisors, whose sum is σ = 195821090. Its totient is φ = 195821088.

The previous prime is 195821051. The next prime is 195821099. The reversal of 195821089 is 980128591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 195440400 + 380689 = 13980^2 + 617^2 .

It is a cyclic number.

It is not a de Polignac number, because 195821089 - 2¹⁵ = 195788321 is a prime.

It is not a weakly prime, because it can be changed into another prime (195821009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97910544 + 97910545.

It is an arithmetic number, because the mean of its divisors is an integer number (97910545).

Almost surely, 2^195821089 is an apocalyptic number.

It is an amenable number.

195821089 is a deficient number, since it is larger than the sum of its proper divisors (1).

195821089 is an equidigital number, since it uses as much as digits as its factorization.

195821089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 43.

The square root of 195821089 is about 13993.6088626201. The cubic root of 195821089 is about 580.7017753905.

The spelling of 195821089 in words is "one hundred ninety-five million, eight hundred twenty-one thousand, eighty-nine".