66195209 has 4 divisors (see below), whose sum is σ = 66213504. Its totient is φ = 66176916.

The previous prime is 66195203. The next prime is 66195277. The reversal of 66195209 is 90259166.

66195209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66195209 - 2²⁰ = 65146633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66195203) 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 in 3 ways as a sum of consecutive naturals, for example, 1697 + ... + 11630.

It is an arithmetic number, because the mean of its divisors is an integer number (16553376).

Almost surely, 2^66195209 is an apocalyptic number.

It is an amenable number.

66195209 is a deficient number, since it is larger than the sum of its proper divisors (18295).

66195209 is a wasteful number, since it uses less digits than its factorization.

66195209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18294.

The product of its (nonzero) digits is 29160, while the sum is 38.

The square root of 66195209 is about 8136.0438174828. The cubic root of 66195209 is about 404.5220373816.

The spelling of 66195209 in words is "sixty-six million, one hundred ninety-five thousand, two hundred nine".