66891866 has 16 divisors (see below), whose sum is σ = 105883200. Its totient is φ = 31630368.

The previous prime is 66891863. The next prime is 66891887. The reversal of 66891866 is 66819866.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66891863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4076 + ... + 12263.

It is an arithmetic number, because the mean of its divisors is an integer number (6617700).

Almost surely, 2^66891866 is an apocalyptic number.

66891866 is a deficient number, since it is larger than the sum of its proper divisors (38991334).

66891866 is a wasteful number, since it uses less digits than its factorization.

66891866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16453.

The product of its digits is 746496, while the sum is 50.

The square root of 66891866 is about 8178.7447692173. The cubic root of 66891866 is about 405.9361891836.

The spelling of 66891866 in words is "sixty-six million, eight hundred ninety-one thousand, eight hundred sixty-six".