66908165 has 4 divisors (see below), whose sum is σ = 80289804. Its totient is φ = 53526528.

The previous prime is 66908161. The next prime is 66908167. The reversal of 66908165 is 56180966.

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 7941124 + 58967041 = 2818^2 + 7679^2 .

It is a cyclic number.

It is not a de Polignac number, because 66908165 - 2² = 66908161 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 (66908161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6690812 + ... + 6690821.

It is an arithmetic number, because the mean of its divisors is an integer number (20072451).

Almost surely, 2^66908165 is an apocalyptic number.

It is an amenable number.

66908165 is a deficient number, since it is larger than the sum of its proper divisors (13381639).

66908165 is a wasteful number, since it uses less digits than its factorization.

66908165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13381638.

The product of its (nonzero) digits is 77760, while the sum is 41.

The square root of 66908165 is about 8179.7411328232. The cubic root of 66908165 is about 405.9691569021.

The spelling of 66908165 in words is "sixty-six million, nine hundred eight thousand, one hundred sixty-five".