66648509 has 2 divisors, whose sum is σ = 66648510. Its totient is φ = 66648508.

The previous prime is 66648479. The next prime is 66648521. The reversal of 66648509 is 90584666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34692100 + 31956409 = 5890^2 + 5653^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66648509 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66648509.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66648559) 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, 33324254 + 33324255.

It is an arithmetic number, because the mean of its divisors is an integer number (33324255).

Almost surely, 2^66648509 is an apocalyptic number.

It is an amenable number.

66648509 is a deficient number, since it is larger than the sum of its proper divisors (1).

66648509 is an equidigital number, since it uses as much as digits as its factorization.

66648509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 44.

The square root of 66648509 is about 8163.8538080982. The cubic root of 66648509 is about 405.4433168301.

The spelling of 66648509 in words is "sixty-six million, six hundred forty-eight thousand, five hundred nine".