66864523 has 16 divisors (see below), whose sum is σ = 74649600. Its totient is φ = 59378080.

The previous prime is 66864521. The next prime is 66864533. The reversal of 66864523 is 32546866.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 66864523 - 2¹ = 66864521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66864521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 174390 + ... + 174772.

It is an arithmetic number, because the mean of its divisors is an integer number (4665600).

Almost surely, 2^66864523 is an apocalyptic number.

66864523 is a deficient number, since it is larger than the sum of its proper divisors (7785077).

66864523 is a wasteful number, since it uses less digits than its factorization.

66864523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 722.

The product of its digits is 207360, while the sum is 40.

The square root of 66864523 is about 8177.0730093353. The cubic root of 66864523 is about 405.8808709185.

The spelling of 66864523 in words is "sixty-six million, eight hundred sixty-four thousand, five hundred twenty-three".