66005647 has 8 divisors (see below), whose sum is σ = 67128480. Its totient is φ = 64888320.

The previous prime is 66005633. The next prime is 66005657. The reversal of 66005647 is 74650066.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66005647 - 2¹⁹ = 65481359 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 (66005657) 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 7 ways as a sum of consecutive naturals, for example, 27903 + ... + 30175.

It is an arithmetic number, because the mean of its divisors is an integer number (8391060).

Almost surely, 2^66005647 is an apocalyptic number.

66005647 is a deficient number, since it is larger than the sum of its proper divisors (1122833).

66005647 is a wasteful number, since it uses less digits than its factorization.

66005647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2753.

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 66005647 is about 8124.3859460269. The cubic root of 66005647 is about 404.1355274317.

The spelling of 66005647 in words is "sixty-six million, five thousand, six hundred forty-seven".