66788165 has 4 divisors (see below), whose sum is σ = 80145804. Its totient is φ = 53430528.

The previous prime is 66788093. The next prime is 66788171. The reversal of 66788165 is 56188766.

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

It can be written as a sum of positive squares in 2 ways, for example, as 50027329 + 16760836 = 7073^2 + 4094^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66788165 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6678812 + ... + 6678821.

It is an arithmetic number, because the mean of its divisors is an integer number (20036451).

Almost surely, 2^66788165 is an apocalyptic number.

It is an amenable number.

66788165 is a deficient number, since it is larger than the sum of its proper divisors (13357639).

66788165 is a wasteful number, since it uses less digits than its factorization.

66788165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13357638.

The product of its digits is 483840, while the sum is 47.

The square root of 66788165 is about 8172.4026454893. The cubic root of 66788165 is about 405.7263093505.

The spelling of 66788165 in words is "sixty-six million, seven hundred eighty-eight thousand, one hundred sixty-five".