66328709 has 2 divisors, whose sum is σ = 66328710. Its totient is φ = 66328708.

The previous prime is 66328681. The next prime is 66328723. The reversal of 66328709 is 90782366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33895684 + 32433025 = 5822^2 + 5695^2 .

It is a cyclic number.

It is not a de Polignac number, because 66328709 - 2⁸ = 66328453 is a prime.

It is a Sophie Germain 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 (66328729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33164354 + 33164355.

It is an arithmetic number, because the mean of its divisors is an integer number (33164355).

Almost surely, 2^66328709 is an apocalyptic number.

It is an amenable number.

66328709 is a deficient number, since it is larger than the sum of its proper divisors (1).

66328709 is an equidigital number, since it uses as much as digits as its factorization.

66328709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 41.

The square root of 66328709 is about 8144.2439182529. The cubic root of 66328709 is about 404.7937963665.

The spelling of 66328709 in words is "sixty-six million, three hundred twenty-eight thousand, seven hundred nine".