66804445 has 4 divisors (see below), whose sum is σ = 80165340. Its totient is φ = 53443552.

The previous prime is 66804431. The next prime is 66804449. The reversal of 66804445 is 54440866.

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 25613721 + 41190724 = 5061^2 + 6418^2 .

It is a cyclic number.

It is not a de Polignac number, because 66804445 - 2¹¹ = 66802397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66804449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6680440 + ... + 6680449.

It is an arithmetic number, because the mean of its divisors is an integer number (20041335).

Almost surely, 2^66804445 is an apocalyptic number.

It is an amenable number.

66804445 is a deficient number, since it is larger than the sum of its proper divisors (13360895).

66804445 is a wasteful number, since it uses less digits than its factorization.

66804445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13360894.

The product of its (nonzero) digits is 92160, while the sum is 37.

The square root of 66804445 is about 8173.3986199133. The cubic root of 66804445 is about 405.7592727141.

The spelling of 66804445 in words is "sixty-six million, eight hundred four thousand, four hundred forty-five".