66665369 has 2 divisors, whose sum is σ = 66665370. Its totient is φ = 66665368.

The previous prime is 66665359. The next prime is 66665371. The reversal of 66665369 is 96356666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66259600 + 405769 = 8140^2 + 637^2 .

It is a cyclic number.

It is not a de Polignac number, because 66665369 - 2¹⁶ = 66599833 is a prime.

It is a super-3 number, since 3×66665369³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

Together with 66665371, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (66665329) 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, 33332684 + 33332685.

It is an arithmetic number, because the mean of its divisors is an integer number (33332685).

Almost surely, 2^66665369 is an apocalyptic number.

It is an amenable number.

66665369 is a deficient number, since it is larger than the sum of its proper divisors (1).

66665369 is an equidigital number, since it uses as much as digits as its factorization.

66665369 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1049760, while the sum is 47.

The square root of 66665369 is about 8164.8863433608. The cubic root of 66665369 is about 405.4775021309.

The spelling of 66665369 in words is "sixty-six million, six hundred sixty-five thousand, three hundred sixty-nine".