66121209 has 24 divisors (see below), whose sum is σ = 119076672. Its totient is φ = 34348320.

The previous prime is 66121201. The next prime is 66121243. The reversal of 66121209 is 90212166.

It is not a de Polignac number, because 66121209 - 2³ = 66121201 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66121201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 47014 + ... + 48399.

It is an arithmetic number, because the mean of its divisors is an integer number (4961528).

Almost surely, 2^66121209 is an apocalyptic number.

It is an amenable number.

66121209 is a deficient number, since it is larger than the sum of its proper divisors (52955463).

66121209 is a wasteful number, since it uses less digits than its factorization.

66121209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95437 (or 95434 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 66121209 is about 8131.4948810167. The cubic root of 66121209 is about 404.3712420151.

The spelling of 66121209 in words is "sixty-six million, one hundred twenty-one thousand, two hundred nine".