66500909 has 2 divisors, whose sum is σ = 66500910. Its totient is φ = 66500908.

The previous prime is 66500899. The next prime is 66500939. The reversal of 66500909 is 90900566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40998409 + 25502500 = 6403^2 + 5050^2 .

It is a cyclic number.

It is not a de Polignac number, because 66500909 - 2⁸ = 66500653 is a prime.

It is a Sophie Germain prime.

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 (66500939) 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 as a sum of consecutive naturals, namely, 33250454 + 33250455.

It is an arithmetic number, because the mean of its divisors is an integer number (33250455).

Almost surely, 2^66500909 is an apocalyptic number.

It is an amenable number.

66500909 is a deficient number, since it is larger than the sum of its proper divisors (1).

66500909 is an equidigital number, since it uses as much as digits as its factorization.

66500909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 66500909 is about 8154.8089493255. The cubic root of 66500909 is about 405.1437969289.

The spelling of 66500909 in words is "sixty-six million, five hundred thousand, nine hundred nine".