66606655 has 4 divisors (see below), whose sum is σ = 79927992. Its totient is φ = 53285320.

The previous prime is 66606611. The next prime is 66606667. The reversal of 66606655 is 55660666.

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 66606655 - 2⁹ = 66606143 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 6660661 + ... + 6660670.

It is an arithmetic number, because the mean of its divisors is an integer number (19981998).

Almost surely, 2^66606655 is an apocalyptic number.

66606655 is a deficient number, since it is larger than the sum of its proper divisors (13321337).

66606655 is a wasteful number, since it uses less digits than its factorization.

66606655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13321336.

The product of its (nonzero) digits is 194400, while the sum is 40.

The square root of 66606655 is about 8161.2900328318. The cubic root of 66606655 is about 405.3584288196.

The spelling of 66606655 in words is "sixty-six million, six hundred six thousand, six hundred fifty-five".