66864490909 has 2 divisors, whose sum is σ = 66864490910. Its totient is φ = 66864490908.

The previous prime is 66864490883. The next prime is 66864490943. The reversal of 66864490909 is 90909446866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 55053583225 + 11810907684 = 234635^2 + 108678^2 .

It is a cyclic number.

It is not a de Polignac number, because 66864490909 - 2⁵ = 66864490877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66864490009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33432245454 + 33432245455.

It is an arithmetic number, because the mean of its divisors is an integer number (33432245455).

Almost surely, 2^66864490909 is an apocalyptic number.

It is an amenable number.

66864490909 is a deficient number, since it is larger than the sum of its proper divisors (1).

66864490909 is an equidigital number, since it uses as much as digits as its factorization.

66864490909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20155392, while the sum is 61.

The spelling of 66864490909 in words is "sixty-six billion, eight hundred sixty-four million, four hundred ninety thousand, nine hundred nine".