66005866 has 12 divisors (see below), whose sum is σ = 105176358. Its totient is φ = 31061312.

The previous prime is 66005857. The next prime is 66005869. The reversal of 66005866 is 66850066.

It can be written as a sum of positive squares in 3 ways, for example, as 65950641 + 55225 = 8121^2 + 235^2 .

It is not an unprimeable number, because it can be changed into a prime (66005869) 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 in 5 ways as a sum of consecutive naturals, for example, 56521 + ... + 57676.

Almost surely, 2^66005866 is an apocalyptic number.

66005866 is a deficient number, since it is larger than the sum of its proper divisors (39170492).

66005866 is a wasteful number, since it uses less digits than its factorization.

66005866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114233 (or 114216 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 66005866 is about 8124.3994239574. The cubic root of 66005866 is about 404.1359743913.

It can be divided in two parts, 6600 and 5866, that multiplied together give a triangular number (38715600 = T₈₇₉₉).

The spelling of 66005866 in words is "sixty-six million, five thousand, eight hundred sixty-six".