66665823 has 64 divisors (see below), whose sum is σ = 113817600. Its totient is φ = 34546176.

The previous prime is 66665803. The next prime is 66665827. The reversal of 66665823 is 32856666.

It is not a de Polignac number, because 66665823 - 2⁶ = 66665759 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66665827) 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 in 63 ways as a sum of consecutive naturals, for example, 647190 + ... + 647292.

It is an arithmetic number, because the mean of its divisors is an integer number (1778400).

Almost surely, 2^66665823 is an apocalyptic number.

66665823 is a deficient number, since it is larger than the sum of its proper divisors (47151777).

66665823 is a wasteful number, since it uses less digits than its factorization.

66665823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181 (or 167 counting only the distinct ones).

The product of its digits is 311040, while the sum is 42.

The square root of 66665823 is about 8164.9141452926. The cubic root of 66665823 is about 405.4784225807.

The spelling of 66665823 in words is "sixty-six million, six hundred sixty-five thousand, eight hundred twenty-three".