66816111 has 4 divisors (see below), whose sum is σ = 89088152. Its totient is φ = 44544072.

The previous prime is 66816107. The next prime is 66816121. The reversal of 66816111 is 11161866.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 66816111 - 2² = 66816107 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66816121) 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 3 ways as a sum of consecutive naturals, for example, 11136016 + ... + 11136021.

It is an arithmetic number, because the mean of its divisors is an integer number (22272038).

Almost surely, 2^66816111 is an apocalyptic number.

66816111 is a deficient number, since it is larger than the sum of its proper divisors (22272041).

66816111 is a wasteful number, since it uses less digits than its factorization.

66816111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22272040.

The product of its digits is 1728, while the sum is 30.

The square root of 66816111 is about 8174.1122453756. The cubic root of 66816111 is about 405.7828904647.

Adding to 66816111 its reverse (11161866), we get a palindrome (77977977).

The spelling of 66816111 in words is "sixty-six million, eight hundred sixteen thousand, one hundred eleven".