66686450189 has 2 divisors, whose sum is σ = 66686450190. Its totient is φ = 66686450188.

The previous prime is 66686450153. The next prime is 66686450191. The reversal of 66686450189 is 98105468666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37973147689 + 28713302500 = 194867^2 + 169450^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66686450189 is a prime.

It is a Sophie Germain prime.

Together with 66686450191, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66686450489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33343225094 + 33343225095.

It is an arithmetic number, because the mean of its divisors is an integer number (33343225095).

Almost surely, 2^66686450189 is an apocalyptic number.

It is an amenable number.

66686450189 is a deficient number, since it is larger than the sum of its proper divisors (1).

66686450189 is an equidigital number, since it uses as much as digits as its factorization.

66686450189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14929920, while the sum is 59.

The spelling of 66686450189 in words is "sixty-six billion, six hundred eighty-six million, four hundred fifty thousand, one hundred eighty-nine".