66649717 has 2 divisors, whose sum is σ = 66649718. Its totient is φ = 66649716.

The previous prime is 66649711. The next prime is 66649729. The reversal of 66649717 is 71794666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54774801 + 11874916 = 7401^2 + 3446^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66649717 is a prime.

It is a super-3 number, since 3×66649717³ (a number of 24 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66649711) 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, 33324858 + 33324859.

It is an arithmetic number, because the mean of its divisors is an integer number (33324859).

Almost surely, 2^66649717 is an apocalyptic number.

It is an amenable number.

66649717 is a deficient number, since it is larger than the sum of its proper divisors (1).

66649717 is an equidigital number, since it uses as much as digits as its factorization.

66649717 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 381024, while the sum is 46.

The square root of 66649717 is about 8163.9277924293. The cubic root of 66649717 is about 405.4457663601.

The spelling of 66649717 in words is "sixty-six million, six hundred forty-nine thousand, seven hundred seventeen".