66138222209 has 4 divisors (see below), whose sum is σ = 68271713280. Its totient is φ = 64004731140.

The previous prime is 66138222191. The next prime is 66138222239. The reversal of 66138222209 is 90222283166.

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 66138222209 - 2¹⁶ = 66138156673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66138222239) 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 in 3 ways as a sum of consecutive naturals, for example, 1066745489 + ... + 1066745550.

It is an arithmetic number, because the mean of its divisors is an integer number (17067928320).

Almost surely, 2^66138222209 is an apocalyptic number.

It is an amenable number.

66138222209 is a deficient number, since it is larger than the sum of its proper divisors (2133491071).

66138222209 is a wasteful number, since it uses less digits than its factorization.

66138222209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2133491070.

The product of its (nonzero) digits is 124416, while the sum is 41.

The spelling of 66138222209 in words is "sixty-six billion, one hundred thirty-eight million, two hundred twenty-two thousand, two hundred nine".