195764209 has 2 divisors, whose sum is σ = 195764210. Its totient is φ = 195764208.

The previous prime is 195764207. The next prime is 195764213. The reversal of 195764209 is 902467591.

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., 171479025 + 24285184 = 13095^2 + 4928^2 .

It is an emirp because it is prime and its reverse (902467591) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 195764209 - 2¹ = 195764207 is a prime.

Together with 195764207, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (195764207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97882104 + 97882105.

It is an arithmetic number, because the mean of its divisors is an integer number (97882105).

Almost surely, 2^195764209 is an apocalyptic number.

It is an amenable number.

195764209 is a deficient number, since it is larger than the sum of its proper divisors (1).

195764209 is an equidigital number, since it uses as much as digits as its factorization.

195764209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 136080, while the sum is 43.

The square root of 195764209 is about 13991.5763586524. The cubic root of 195764209 is about 580.6455446141.

It can be divided in two parts, 1957 and 64209, that added together give a palindrome (66166).

The spelling of 195764209 in words is "one hundred ninety-five million, seven hundred sixty-four thousand, two hundred nine".